Meet the maddest ever Lambo tuner

The backstreets of Kabukicho are emphatically not guidebook Japan. There are no raked gardens of tranquillity or mile-high electronics shops. No giant Hello Kitty effigies or schoolgirls giggling behind their hands. Not real ones, anyway.

We're in the back end of Tokyo's red light district. Tangled in a cat's cradle of power lines, it's a scrubby fretwork of low-rise corridors, barely wide enough for the blacked-out Benzes that routinely slip past. Between the love hotels and host bars and noodle shacks, there are thousands of pot plants, incongruously meticulous. You wonder who waters them, and with what.

Pictures: Luke Huxham

This feature first appeared in the January 2015 issue of Top Gear magazine

There are three types of people here - irredeemably drunk salarymen limping into skin bars, self-conscious lost boys distressed to rebellious perfection, and groups of men moving with slow, cinematic confidence. Their suits are perfect, and they're the ones to worry about. Yakuza, Japan's Mafia - the largest organised crime syndicate in the world. Revered as folk heroes, like modern-day samurai, they hide behind a paper screen of Western sophistication. Related by blood: theirs or other people's.

Today, there's a fourth. There's only one of him, and he's called Shinichi Morohoshi. His shoes are disco balls. His hair is electric. His jewellery hurts to look at. He's dressed in Tokyo's psychosis, like the ultimate aspiration of the light show that defines this city. Despite his open ties with Yakuza, he's playful and disarming.

Familiar with my coarse British sensibilities, he extends a hand to shake (most locals just bow), and I'm presented with a business card that's only got his name on it. As we go through the reciprocal rigmarole of Japanese card swapping (receive with both hands, thumbs forward; study intensely; place in the pocket closest to your heart) I spot a diamond-studded Rolex. Morohoshi likes diamonds. They're on his jumper, his jeans, his phone, his Lamborghini...

Now, this is a city that suffers from amazement fatigue. The neon lights are set to Head Trauma, and roughly three quarters of the toilets talk (no, really) - defecate into a robot's mouth every day, and you'd stop being dazzled, too. But a diamond-studded Diablo Super Veloce in the Mafia-run sleaze district. That'll turn heads. Add a hot-pink mirror wrap, and the camera phones come out. LED rope lights and strobes in the intakes? The throngs descend into a full, table-rattling spasm.

"I like flashy cars," says Morohoshi-san. "And I like dangerous people. I used to spend a lot of time working here when I was younger, but my business trading goods was in the grey area." He gives his smile another careful centimetre. "Well... black. But now I concentrate on my cars and [legitimate] work. Still, it's important for me to remain part of this group, and this place. I used to trade with Yakuza here. They are good-hearted, they respect friendship highly, and there are lots of people to help with lots of things. Anyway, it's important to remember your past."

Morohoshi hasn't always been a car guy. As a young man, he used to have a motorcycle customised in Bōsōzoku style. Literally, the word means ‘violent running tribe', but the reality's a bit more civilised. A bit... The bikes are part British café racer, part American chopper, but mostly incomprehensible madness. Neons are added, exhaust pipes are radically oversized, each fairing carries the flag of its club, and they're ridden at maximum attack through heavy traffic.

"To bōsō is to be in a criminal gang, but you don't look for crimes to commit... apart from traffic crimes. It's more about making ordinary road bikes stand out. It feels good to ride with your gang, but you get in trouble. [From 2004] Japanese police were given a lot more power to arrest groups of bikers. It's hard to ride with your friends these days and stay out of trouble. At some point, you have to accept that you can't live like that. For me, that happened well before the police lock-down. It was the day I saw a Lamborghini.

"I was 17, and it was New Year 's Eve. I heard this thing long before I saw it - it had such an intense exhaust note, I was completely mesmerised, and had no idea a car could make so much noise. We would spend hundreds of thousand [yen] on our bike's exhaust, but this was just... louder. After a few seconds, I could see it. It was a black Countach driving down Nakasendō Road. I told myself I was going to buy a Lamborghini. I had to buy a Lamborghini.

"After 16 years and a few arrests, I bought my first - a Diablo. In the beginning, I was quite happy with it. It was loud, like the Countach, and fast, and beautiful. But then I started going to owners' club meetings. There, I felt like I wasn't... standing out. I like to stand out. I need to stand out. So I began thinking of ways I could make my car look different. When I was planning [my customisations], I took inspiration from bōsōzoku bikes. And Darth Vadar. Both are futuristic and powerful, and inspired me to think differently to other people [tuning cars].

"I had to go to five different shops before I found anywhere willing to make the modifications. The owners just refused - they were too scared to change my car, even though I brought the LEDs with me in a box and big piles of cash. I even begged them, but it was an expensive supercar, and they wanted nothing to do with me. Eventually, I found a small garage in Tokyo that would do what I wanted. Bigger, louder exhausts, flashy wraps, LEDs, diamonds: Morohoshi style.

"When I first arrived at the official Japanese Lamborghini Club meetings after I'd changed the first Diablo, nobody liked it. Not one other person. It was too much for them - they're weren't used to this style, and they didn't understand it. They were normal businessmen and hadn't had the youth I had. But I was persistent, and patient with them. Eventually, they learned who I was and where I came from."

"People started asking questions, and when they heard I'd bought another car, they wanted to know what I was going to do with it. This, the Murciélago Roadster and the Murciélago Coupe I own, all received great interest. So has the Aventador I'm currently customising. There's something different about each of them, but also a common [thread]. Every time I build something, I create something original that's still me. It's what I'm known for."

Thing is, Morohoshi's brand of originality is a little... divisive. His modifications have distanced him from the more traditional Lambo enthusiasts, and some modifications - particularly his air horn, which plays the Godfather theme tune - have raised a few eyebrows when he's taken his car abroad.

"I attended the [factory-backed] 50 Years of Lamborghini rally earlier this year [2013], and before it started, I went to fill up my SV in Milan. All the lights were on, and I was playing the air horn. Somebody must have been watching, because the next morning I was asked to behave better. But I kept it down, and at the end Lamborghini CEO Stephan Winkelmann signed my car."

"It's funny to me that I'm distanced. Whenever I'm overseas, other Lamborghini owners love me. They can't believe what I've done. Even the public were fascinated. In Italy, there were crowds cheering at my car and gesturing me to play the horn, even in traditional Mafia towns. I can understand why some people, and why some Lamborghini enthusiasts find my modifications..." He pauses, searching for the mot juste. "Unnecessary. But I don't care.

"I'm not what you'd associate with anything Lamborghini - the company, other owners - and we've always had a troubled relationship. Traditional enthusiasts wanted to keep away from me in the early days, so I had to start my own group - Akuma Shukai. It means ‘Diablo Meeting' in Japanese, and we welcomed everyone. No matter where they were from or how they modified their car. It ended five years ago because of rivalry and jealousy - cars like this appeal to a certain kind of person, and they don't tend to mix well with each other. But each car from our group stood out, they were unique. We started something. We started bōsō Lamborghinis."

Morohoshi drops into his Diablo, and starts the engine. We're headed across Rainbow Bridge - it ties together Shibaura Pier and Minato town across Tokyo Bay, and it looks like a Mario Kart level. Lamps on the wires supporting the bridge phase between three colours and dapple the road with colour. As signs written in kanji fly overhead, it's like passing through a stargate into the stereotype dimension. Right on cue, a heavily modified Nissan Silvia zips past, all turbo whistle and dump valve. It has ‘EXCITING TEAM RISK!' written on the door.

Once you've been battered round the head with context - something Japan manages with alacrity - the Diablo, despite its underlights and strobes and regurgitated Dolly Mixture palette, doesn't look ridiculous. It's shaped by this city; it belongs here. A place that's not alien per se, but full of things aliens might do and eat and drive if they'd been given a city, taken an online course in Being Human, and were told to try and slip onto Earth under the radar.

We pull onto the intestinal wangan, the Bayshore route of the Shuto Expressway that connects the Chiba and Kanagawa prefectures. Morohoshi says: "This is the old Mid Nite Club racing area." To a petrolhead, this is as storied and ancient as the temples that pockmark Tokyo. The Mid Nite Club was formed in 1987, and you could only join if your car hit 160mph. But to be competitive, you had to have a 200mph car. The group disbanded in 1999 after a fatal accident where two bōsōzoku bikers were killed and eight motorists hospitalised. Six of them were members of the public.

"This is not a street-racing car," says Morohoshi, pulling the scissor door shut as we leave a service area. He hits the clutch and revs hello to the congregation of tuners lining the car park; R32 GT-Rs, Honda S2000s, EK Civics all rev back. Then, before I can draw breath, let alone colour it in, he detonates back onto the wangan, 529bhp tugging at the skyline. The irony's not lost.

When we eventually catch up, Morohoshi and his friend Shinya Egawa are laughing at our dim-witted Toyota Vitz (Yaris over here) hire car. "Slow car!" shouts Egawa. Yeah, cheers mate... Morohoshi is Egawa's modding hourensou - a sort of mentor and guide. Egawa has a Gallardo coupe, and under Morohoshi's careful tutelage, he's fitted it with a hologram wrap, and plans a similar light show to his sage. Morohoshi says: "There are many people that want to have my style. I encourage all of them. I don't sell cars, I don't own tuning shops, but I'm the best producer of modified Lamborghinis there is. I think of myself as a consultant. I helped Egawa-san plan his modifications.

There are five other people like him that want cars I've designed. I have shops I can go to that are brave enough to cut into supercars - this is hard to find. People need a Morohoshi senpai." Egawa says: "He supervises, and I can ask him for advice. He's like a big brother."

Big in Japan, but rest-of-world orders are non-existent. Not that a gaijin - a Westerner - could find him. "I keep a very low profile in business. Sometimes you need to be hard to find. Not because I'm Yakuza - I'm not. But then no real Yakuza would ever tell you if they were..."

Though this anonymity threatens to change. At the next Tokyo Auto Salon - Japan's annual modified car show - Morohoshi will be exhibiting. Not just his armada of modified Lambos, but a Murciélago concept. Buried somewhere under a kudzu of ornamentation, it's ostensibly a Sesto Elemento-flavoured bodykit, with added anarchy. We're promised it can be built.

Would Morohoshi-brand Lamborghinis work anywhere else in the world? No. And resolutely not in short-back-and-sides Britain. But this pink Death Star of a thing, camp as Christmas and fine in a way entirely of its own, has all of Morohoshi in it. Like it's been formed, in a moment of careless serendipity, by the Kabukicho district.

Anyone can buy a supercar, and it says precisely nothing about them. This Diablo tells you everything you need to know about Morohoshi. And how little he cares what you think.