Back in 1974 Porsche created the 911 Carrera RSR Turbo 2.1. Despite being the Stuttgart firm’s first ever 911 turbo racer, it finished second overall at Le Mans beating every sports prototype bar one. Powered by a 2.1-litre flat six developing 500bhp, it was a lightweight 815kg monster, devastatingly effective straight out of the box.

Cars such as the RSR Turbo helped forge the early reputation of turbo-boosted cars as wild, lairy machines. And almost ever since it’s been about taming them, finding ways to eradicate the lag, soften the boost. Fifty years of development on, and Porsche’s own 911 Turbo S road car now has electric motors to help spin its turbos. It’s a remarkable piece of engineering, but in many ways does its best to conceal the fact it has turbos at all.

The Gunther Werks Turbo isn’t like that. This is a car that harks straight back to the good old days of turbos, when lag was huge and thrust was hard. Gunther Werks doesn’t particularly cite the RSR Turbo as inspiration but it legitimately could. Like the OG, its flat six is air-cooled and only has two valves per cylinder. But then: a pair of chunky turbos, rather than a single and, at 4 litres, almost double the engine capacity.

The 992.2 Turbo S we mentioned earlier has 701bhp. The Gunther Werks Turbo has 850bhp. It weighs 1230kg. Explosive doesn’t really cover it. That RSR had a colossal power-to-weight ratio, 613bhp/tonne. The latest Turbo S can ‘only’ muster 406bhp/tonne. Here it’s 690bhp/tonne.

Every restomod firm needs a USP, especially one restoring and modifying Porsche 911s given how many use that as their starting point. Well, there aren’t many others sending cars out the door with this much power. Or more – earlier this year Gunther Werks launched the F-26 which, on E85 fuel, develops 1067bhp. I drove it. It was terrifyingly brilliant, perhaps the most intense road car with a roof I’ve handled.

The Turbo was the starting point for the F-26, the car where California-based Gunther Werks realised they’d perhaps gone a bit too far and if they wanted to go further they’d have to re-engineer the whole chassis. So what’s what it did for the F-26, fitting double wishbone front suspension, rose-jointing it all round for better control, upping chassis rigidity yet further.

“This is a car that harks straight back to the good old days of turbos, when lag was huge”

The Turbo doesn’t have the same level of polish. It’s more wayward, wilder and feels more like an old 911. You find yourself driving around the flaws, being wary of the short wheelbase, the lift-off, the lag, the boost, everything really. The main method of coping with 850bhp is the tyres, enormously wide 335s at the rear, 295s at the front (which restrict steering lock considerably). This is not a chassis car, it’s a power car where the rest has to cope.

Besides the tyres, stiff springs and JZM dampers try their best to control wheel movements. I’d argue its all a bit too stiff. Even with the dampers in Comfort mode, the Turbo feels rigid on the road, the wide rubber chasing cambers and tugging at the steering. Those tyres make a din too, so long journeys are tough; fuel thirst is prodigious.

“Bespoke carbon body panels are fitted, making the 993 look like an older 911, giving that race vibe”

Because of the short, wide stance, the rear-mounted engine and the firm suspension, the chassis has a small sweet spot. Too much speed into corners and the front stumbles over itself into understeer, too little and you’ll want to accelerate mid-corner, which could go one of two ways depending on how the turbos are feeling. Long story short, keep corners and straights very separate, just be patient and wait to unleash the hit. The anticipation is worth it.

The start point for all of Gunther Werks’ conversions is a 993-generation 911, the whole thing stripped back, reinforced and rebuilt from the ground up. Bespoke carbon body panels are fitted, making the 993 look like an older 911, giving it that race vibe. It’s not as gorgeously detailed or as aesthetically pleasing as one of Singer’s recreations, but Gunther Werks has found its niche.

Inside, the race theme continues. There’s a titanium rollcage, a carbon-fibre plinth covers the rear compartment, the seats (Gunther Werks’ own design) are single-piece carbon buckets with a removable headrest pad to give more space for a helmet. And yet despite all this it’s not really a track car. What it is, is a fairground ride. It’s a car for quick, addictive hits. To go out to a quiet road and remind yourself what it feels like when the rev counter swings past 3500rpm and for the next 3500rpm you’re basically along for the ride, fingers curled like claws around the steering wheel.

“There’s so much enjoyment to be had just hearing the turbos start to gust and fizz”

The powertrain is a triumph, just so much fun to use. Yes, you need to be careful with it, but that’s what makes it exciting, the knowledge that you could overdo it if you prod too hard at the hornet’s nest. There is a motor sport traction control there to save you from the turbos’ worst excesses, but it’s not a full stability control system. You have to take responsibility – a fact that is rammed home by the presence of a manual gearbox. Open gate, tight shift, lovely clicks and clacks, the perfect way to access the power, the deep, chuntering soundtrack and fury.

Because you don’t have to max it out all the time – there’s so much enjoyment to be had just hearing the turbos start to gust and fizz, lifting off for the overrun barrage, the flat six rumble and churn. Mechanically it feels really robust (Gunther Werks backs it up with a five-year, 100,000-mile warranty), like a period piece rather than a new car. I like that the cabin’s modern touches, the USB slots and CarPlay-equipped hi-fi, are hidden away.

It costs $950,000 (£705,000) before you add options, way more than a standard £200,000 Turbo S which would show it a clean pair of heels on a good road, usefully less than the $1.5m (£1.15m) charged for an F-26. But for sheer cling-on-for-dear-life excitement, there’s not much to touch it. We’ve done so well at taming turbos, we’ve forgotten how thrilling they can be. The Gunther Werks Turbo reminds us.

GUNTHER WERKS TURBO

• ENGINE 4 litres, twin turbo, rear-wheel drive
• CHASSIS Donor 993, reinforced
• BODY Carbon front fenders, rear quarter panels, skirts, roof, front hood, front bumper, rear bumper, rear wing, rear duck tail (optional)
• TRANSMISSION Getrag six-speed manual
• SUSPENSION Bespoke JZM/TracTive adaptive suspension, remote reservoir adjustable dampers
• POWER 850bhp (track mode)
• WEIGHT 1230kg