Mechatronik M SEC review: a great reason to stick a kidney on eBay

What’s that?

Something that will make you want to alter the wording on an ailing relative’s will, buy too many lottery tickets, or do a light bit of bank robbery. In less felonious musings, a restomod Mercedes Benz SEC by German meisters Mechatronik.

The basic blueprint? A C126 SEC re-made entirely and then equipped with the 6.2-litre M156 naturally-aspirated V8 from 2007-2015 and the 7G-Tronic auto. Two of Mercedes’ best ingredients in one delicious meal. And yes, the M156 was badged ‘6.3’ in honour of the M100 motor, but because the capacity is 6,208cc, it’s a 6.2 in reality. Sorry, nerd here.

Yet another restomod? Yawn. 

Stop. Right. There. Yes, it’s another re-work, but when restomods are done right, they really do stir the emotions like nothing else. And this one is done right. With respect and thought and a really boring attention to detail. It’s the kind of car you want to drive every day, in every condition – not some glazed special that’s only effective in one per cent of situations, or a track refugee that can’t be used on the street. There are very few cars I genuinely lust after, this is one of them.

Okay, okay, I get it – you like it. But what’s actually gone on here?

Right. The meat of it is a Bruno Sacco-designed C126 SEC from back in the day, the two-door coupe based on the 126-series S-Class. So that’s big-body ‘Benz era, pillarless, big presence even in standard format. Understated, but not necessarily under-the-radar. One of these, you must take to Mechatronik in Pleidelsheim, north of Stuttgart. At which point, it all kicks off.

Run me through the basics?

It’ll have to be basic, because you probably want to spend less than the rest of today reading this. But the first step is complete disassembly, down to component parts. Keeping as much of the original car as possible. The body is completely paint and grime chemical stripped to a naked shell, then cathodic dipped – basically electro-chemical über rust-proofing and anti-corrosion that doesn’t miss bits.

Then reassembled with new bolts, screws and panel gaps. There are no major mods to the body apart from correction, simply because these cars don’t really need it. So no extra welds or subbed-in bracing. Which brings us to…

… the widebody.

Do a light bit of search-engine sleuthing and you’ll find an AMG 500 SEC. Full wide-arch monster. The Mechatronik is somewhere in between. So there’s a bodykit made entirely from carbon fiber. Front and rear bumpers, wings, side skirts, side cladding and slim rear spoiler are all melded, leading to a car that’s very slightly more aerodynamic than the original. Which goes to show how precise the Mechatronik car actually is. And it also looks excellent – sort of stock in-period.

The assembled chassis is then painted, which is to undersell the gloss. Customers can have basically any shade, and you can leave the carbon bits unpainted, completely covered up or kind of ghost-tinted, where you can see the carbon trim peeking through whatever bits of bodywork you find most aesthetic. Personal preference would see it covered, but you can have what you want. One Mechatronik employee follows each car through the build process to ensure continuity and quality control. Imagine that for mass production.

One side note: the headlights come with two options – the original lights with a warm candle-esque glow and brighter main beams, or a full LED system with slim daytime running lights. If you want a more technical (and obvious) style, then the LEDs make the M SEC look more modern. We’d go with the original look. Similarly, Mechatronik also doesn’t supply the grille with the Mercedes star in the middle. The suggestion is that it would be easily replaced…

It’s a good base, then. But what about the good bits?

SECs always had big V8s. So the natural choice for an OEM+ restomod had to be the M156 produced between about 2007 and 2015. Plenty available (E63 AMG etc), powerful and naturally-aspirated.

Interestingly, it’s not tuned in this application, just blueprinted and refreshed. With 500bhp and 465lb ft in a car that weighs around 1,700kg, that’s enough – and reliability and ease-of-use were more important here than internet headlines.

Mate that to the rear-wheel drive architecture and accompanying 7G-Tronic auto and you’ve got a stellar engine/transmission package nestled in one of Merc’s most iconic bodyshells. That exhales through a classic stainless steel exhaust with a classic dual tailpipe, which you can have tuned to your personal preference of loud.

Power is nothing without control though, no?

Absolutely, so you’re looking at Öhlins suspension based on the ‘Road and Track’ spec stuff, though not coilover, but designed with this SEC in mind. Dual-flow valving, set up how the customer desires, but with a definite bent towards fast GT rather than track car.

Interesting here that Mechatronik does a more comfy version of the M SEC with classic style and interior, and a ‘GT Package’ (the silver car above) without back seats, front buckets and a nearly 100kg weight loss. That car gets the same powertrain (although a fruitier tune for that exhaust), but can have more aggressive suspension set up as well as a bigger brake kit. The standard Brembos are 360mm/front, 330mm/rear; the GT Package 390mm on the front with braided steel brake lines. Both are powerful and mightily regular – and easy to modulate even on slippery surfaces. 

Wheels come in two distinct styles, both aping 1980s retro designs, all 19 inches. There’s a classic monoblock, which can be colour-coded for extra scene points, or a machined cross-spoke. Both look fantastic, and are wrapped in modern Michelin Pilot Sport 4Ss. There’s a Cup2 option tyre for the GT Package, but again, that feels a bit wrong for an SEC, even with the racy bits.

What about the inside?

Ah, yes. Here’s where it gets even better. Seating options? Four. Original seats restored, big squashy, sausagey electric classic seats, sports comfort seats or sports buckets. The GT Package comes with the sports buckets, which are fine, but the correct decision here is the classics – complete with the original electric push buttons for lumbar support and heating.

The architecture is as it was – no changes – but you can have modern woods and inlays, whatever leather you require. And Mechatronik keeps all the big-button and original vent goodness; the knobs and switches feel like they should. This isn’t an old SEC doing cosplay – it’s an old car with bionic bits.

This isn’t an old SEC doing cosplay – it’s an old car with bionic bits

So the headliner, door cards, carpeting… it’s all new, and in any colour or combination you can think of. The only big change being a dialset that has three gauges – analogue on the right-hand side pair, a round digital display tucked into the left-hand side porthole. That contains all the usual ‘modern’ info like gear position, mode, mpg – all of that.

And yep, all the Sport and Comfort modes from the original gearbox work. You can option paddle shifters behind the wheel if you prefer, or delete them for an OG look – though worth noting that Merc did very small paddles at this point, so they’re not particularly intrusive to the vibe.

Radio and hifi is a Blaupunkt classic – so behind the ‘tape deck’ is a USB and aux port for streaming, and you can have ten speakers and three subs for a total of 1,560 watts of ‘80s hits. It’s all essentially 120mph of autobahn cruising heaven.

So it’s an art piece just sitting there. But how does it drive?

Spectacularly well, if you’ve ever driven an original SEC – or even an older S-Class. The noise is pure Merc V8, including the classic ‘BRAAA’ on start-up, which mellows to a muscular woofle. The GT Package car has a louder note throughout, but can get a bit boomy in this development car, and we’d avoid – the SEC is better sampled without the boy racer in attendance. 

But on the road, there’s so much to like, it’s hard to get your head around. The steering is relatively slow compared to modern cars, but be positive through the first five degrees of turn and the M SEC whips neatly into corners, controlling the body perfectly. It’s not set up to be flat – there’s body roll – but it just lets you know what’s going on with the tyres and grip.

And it sucks up bumps and road imperfections like a champ – then cruises on a derestricted autobahn at 120mph with only a bit of flutter from 1980s aero. Safe, stable and stupendous. But always, always a GT.

That slight ease from the rack at the wheel makes it relaxing on A-roads, the first eighth of an inch of softness at the top of the brake pedal making for soft stops in town without conscious effort. It’s comfortable, and swoopy and marvellous – an SEC with plenty of bite and modern manners, without losing the essential nature of the thing.

What’s the verdict then?

You have two kidneys, do you really need them both?

Photography: Alex Tapley