Porsche 911 GT3 Manthey review: expensive, but the suspension is utterly phenomenal…

I can’t take that seriously. It’s got carbon wheel spats.

It does. But you don’t have to have them. They remove with an allen key. Or you can avoid buying them in the first place. There’s a fair bit to unpack here – as a Porsche technician might mutter to themselves.

So what are the basics?

Manthey makes Porsches go faster. It’s been doing this for a long time, first as a race team, then as a parts supplier for road and race cars and now as a builder of whole kits. Which is what you’re looking at here – attached to a current generation 992 GT3.

This isn’t the first time Manthey has done a complete kit – the first was for the GT2 RS, then they did one for the Cayman GT4 RS and most recently for the fearsome GT3 RS.

Because Manthey is part owned by Porsche and they don’t want to have to go through the whole homologation and legislation procedure for a track kit, it has to be perfectly aligned with the regular GT3 – has to have the same emissions, be the same weight, the same power, as clean through the air. 

So no engine mods, no weight reduction?

Correct. The Manthey Kit for the GT3 consists of brake, aero and suspension upgrades. It costs £56,000. Including VAT. On top of that this car has a £12,000 carbon pack (bonnet vents and engine cover), £9,160 lightweight aluminium wheels, a £668 pair of tow straps and Manthey brake pads (£1,295 for the fronts, £1,175 for the rears). All told that’s an entire Cayman GT4 of options: £80,298.

Let’s get back to the kit – how does Manthey justify £56k?

We’ll get on to the details, but the first thing to bear in mind is that Porsche is a majority shareholder in Manthey so insists that every component Manthey develops is as durable as anything that comes from the factory.

Take the fancy dampers – they’re built by KW to Manthey’s own specification. They have to survive one million compressions, equivalent to driving 200,000km. In testing on the rig, the spring broke after 700,000 damper compressions, so they had to start again. The springs themselves had to undergo freeze/thaw, salt immersion and all sorts of other tests and still perform exactly as intended.

The fancy dampers... have to survive one million compressions, equivalent to driving 200,000km. In testing the spring broke after 700,000, so they had to start again

Porsche offers an extended warranty of up to 15 years, and since these are official Porsche kits, that applies to Manthey too. So the development process is long, involved and costly. Hence £56,000.

And what about the kit itself?

It’s designed to focus the GT3 for more driver reward – on road as well as track. That’s crucial as we’ll find out. It’s emphatically not just about faster lap times.

It’s cleaner through the air than a winged GT3, yet develops significantly more downforce – 540kg at 177mph. An extended (by 12mm) splitter channels more air under the car where it meets an entirely reworked underbody with elements up to 150cm long that direct airflow where it’s needed. The diffuser at the back is from Manthey’s GT3 RS kit.

The rear wing endplates are bigger and curve in to help keep air attached to the bodywork over the ducktail element. Those wheel spats mean less turbulence.

The brakes pads may be extra, but included are steel braided brake hoses for better pedal feel. The lightweight aluminium 20/21-inch wheels save 6kg around the car. They’re only 1.4kg heavier than Porsche’s magnesium wheels. If you want to beat that, Manthey has a magnesium wheel set. That’s around €20,000 (£17,300).

Then there’s the flim-flam that’s thrown in: Manthey badges and illuminated door entry guards, stickers and so on.

Didn’t you mention suspension mods as well?

I’ve saved them for last for a reason. Aero is clever stuff, but you don’t feel it. The suspension changes you feel all the time. They are the single most impressive aspect of the whole package. And since you can have them from Manthey’s parts catalogue independent of anything else, the upgrade you should genuinely consider.

Springs first. Compared to the regular GT3 the fronts are 20 per cent stiffer, the rears seven per cent softer. The dampers are no longer adaptive, so switching modes on the steering wheel doesn’t affect the ride. They’re four-way adjustable (compression/rebound both for high/low speed), but you’ll be removing wheels and reaching into wheel arches to do it – tricky given the centre lock wheels are torqued to 700Nm (the wheel spats to just 15Nm though).

The dampers have 12 stops, but the difference between what Manthey recommends for road and track is just two or three clicks. Not much difference, you’re thinking.

Bet it’s going to be really stiff.

It rides significantly better than a regular GT3. Genuinely. It’s calmer, flows along roads better, and actually feels markedly softer at both ends. It’s weird to start with. On undulating roads it’s placid, occasionally feels almost lazy alongside the sharper-reacting GT3.

But as I drove it more, what it reminded me of was a top end rally car. The dampers feel like they’re adapting to your driving. Pick up the pace and they resist roll, squat and dive, but do so in a way that rounds the edge off every movement.

The result is a more exploitable, more playful GT3.

And on track?

Manthey has a very, very proven track record. That’s why Porschephiles get their bits in a twist. Olaf Manthey, a successful DTM and Porsche Supercup driver, set up his own race team in 1996. He started winning almost immediately and hasn’t stopped since.

No-one has won the Nurburgring 24 hours more (seven times). Manthey has also had six class wins at Le Mans, been DTM champion twice in the last three years, and had eight world championships in the FIA WEC program.

It has been so successful that in 2013 Porsche took a controlling stake, which led to road car kit development after Lamborghini and AMG bettered the regular GT2’s 6m47.3 ‘Ring lap time. Wanting to fight back, Porsche turned to Manthey and in June 2021 went back to the Ring and with the same driver, Lars Kern, set a lap time of 6m43.3 – four seconds faster. Manthey has just performed exactly the same trick with the GT3 RS, Jorg Bergmeister lowering the lap time from 6m49.3 to 6m45.4.

But you weren’t at the Nurburgring?

Nope, Thruxton. The UK’s fastest circuit, 150mph through Church etc. It’s an intimidating place, but as a way of lowering your stress levels, the GT3 Manthey takes a hell of a lot of beating. Again, it’s the calmness of its manners that’s most striking. It never seems rushed or hurried, always has complete control of its movements. It doesn’t fidget or bite or give you anything other than positive signals. And time to react – it appears able to slow the process of driving down.

I can’t say I noticed the brakes being any more positive underfoot – they were already phenomenal. It was very stable at high speed, but better than a normal winged GT3? Not noticeably.

But the confidence it gave me to attack the fast corners was incredible. The front end does bobble through corners, in the car I’d jiggle in the seat, but it all feels incredibly trustworthy, appears to give you more time to react and respond. The last time I was at Thruxton was for the AMG One and Aston Valkyrie twin test. I reckon I was travelling faster around significant chunks of the track in this.

The last time I was at Thruxton was for the AMG One and Aston Valkyrie twin test. I reckon I was travelling faster around significant chunks of the track in this

Yes, it grips outrageously hard (I drove it on both Michelin Cup 2 and Cup 2R), but it’s the usability and communication of that grip for non-professional racers that makes this so approachable.

Does the powertrain feel like a weak link?

It’s weird isn't it. Only a little bit over 500bhp when everyone else has 7 or 800 and yet this sets faster lap times. It’s still a masterpiece, this engine – for its 9,000rpm soundtrack, sheer determination and spectacular gearbox, more than is actual thrust. But still, 0-62mph in 3.4 seconds and a 193mph top end from a 4.0-litre, 503bhp flat six that’s still naturally aspirated is a reason to be excited.

But a GT3 costs £158,200 these days doesn’t it?

Which means you’re looking at around £215,000 with the basic Manthey kit fitted or – as is the case here – a final bill of £280,517 for all the Manthey bits and Porsche factory options (which here include the Weissach Package, PCCB brakes, lightweight bucket seats, LED lights, front axle lift and more).

Should I do it to my GT3?

We’re well into silly money territory. You could have a used GT3 RS (you’ll never get an allocation for a new one…), a nearly new McLaren 750S, an actual new Artura or GT63 Pro or Aston Martin Vantage…

But the way to think of this is as a showcase. You don’t have to have all the bits. Just go to Manthey and have the bits you actually want. Their biggest seller, it won’t surprise you, is the windscreen sticker. Me? I’d fit the springs and dampers to a manual GT3 Touring and be happy forever.