Bovensiepen 05 GT driven: 790bhp successor to the Alpina B5

Close

News

5 mins read

17 June 2026

Journalists gathered to try the Bovensiepen Zagato in Austria were surprised when a second Bovensiepen model was suddenly revealed – one with 790bhp, and not simply for us to ogle.

Anybody who appreciates the back-catalogue of the Bovensiepen family – custodians of Alpina until the naming rights transferred to BMW last year – will recognise the conceptual similarities between the 05 GT, as this second model is known, and the now-extinct Alpina B5.

Take a mainline BMW, give the styling a shot of sporting elegance, revise the suspension with comfort in mind, turn up the wick and ply the cabin with leather. The format served Alpina well for decades, and now that BMW will use the Alpina name to purvey lavish versions of the 7 Series, the Bovensiepens needed little encouragement to continue their fine work on the 5 Series.

The key difference between this 05 GT and B5 BiTurbos of old is that here the engineering revisions to the donor car are no longer quite as involved. There is no reinforcing of gearboxes, no extra radiators, or chassis bracing. Then again, there needn’t be. The 05 GT isn’t based on an M550 or suchlike but on the full-blown G99-generation M5 Touring (and only the Touring, because there will be no saloon for the foreseeable future). Note that buyers will need to order the car through Bovensiepen Automobile, which is not offering the 05 GT package as a retrofit to used M5s.

Taking such a brute as the starting point for the 05 GT makes for some extraordinary numbers, in this case 790bhp and 811lb ft, the latter from barely above tickover. The claimed 0-62mph time is "less than" 3.6sec, while top speed is given as 190mph, though because the car is geared to hit 227mph even in seventh, the double-tonne must be fair game on an autobahn. All said, this car is faster than an M5 Touring.

Having briefly considered binning it off, in the end Bovensiepen elected to keep the electric portion of the M5’s plug-in hybrid powertrain but left it untouched. The motor inside the eight-speed gearbox therefore continues to make around 200bhp, and of course it means the 05 GT can operate as an EV, albeit only for 35 miles or so.

Back to top

Meanwhile the twin-turbo 4.4-litre petrol V8 gets new intake plumbing and a titanium Akrapovic exhaust from the silencer back. It alone is responsible for the 05 GT’s 72bhp uplift over the regular M5’s output. Flybys at the Salzburgring racetrack, where we drove the 05 GT, were riotous events reminiscent of low-flying jet aircraft.

Elsewhere, the M5’s M Adaptive dampers have been retuned and the 05 GT is fitted with its own bespoke Eibach springs, as well as new strut-tower braces. The staggered wheel set-up of the regular M5 is also dispensed with and 21in alloys (with milled spokes) are fitted all round. Model-specific ‘BOV’-marked P Zero R tyres, bespoke from Pirelli, complete the package with an M5-matching contact patch.

Bovensiepen doesn’t tinker with the tuning of the steering or the rear-steering, or the four-wheel drive system, which behaves as per the regular M5, with its myriad of modes and traction control settings.

What it has tinkered with, and tinkered well, is the styling. This is the work of Frank Stephenson’s studio and it offers a wholesale revision of the standard car’s porcine thuggery. A black pin-stripe down the flanks – along with the concave sills intended to reduce visual weight – is bookended by subtly sporting bumpers and neat roof spoiler. It will take a while for a bumper script that reads ‘Bovensiepen’ rather than ‘Alpina’ to feel normal, but this is a smart styling effort that strikes the right tone on a challenging canvas.

Which brings us to the interior, where it is a similar story to the outside. All the saddlery expertise that the Bovensiepens accrued while in command of Alpina has been brought to bear and it is superbly plush in here, with endless potential for customisation, including embossing of the headrests. It’s just a shame that the donor car is so plastic-heavy across the dashboard. It cheapens the ambience, though this can hardly be held against Bovensiepen Automobile, whose diligence in maximising comfort extends to offering several tyres of piping for the upholstery.

Back to top

Comfort is something the 05 GT ought to do well on the road. We won’t know for certain until we drive one in the UK, but the way this revised chassis dealt with the fiendish undulations of the Salzburgring was promisingly languid but underpinned with confident-inspiring control. That said, Bovensiepen ought to offer 20in wheels with a little more sidewall, just to be on the safe side in terms of secondary ride. Unfortunately, a grand total of six laps doesn’t permit much more in the way of meaningful real-world dynamic analysis.

Performance? Monumental; move on. Towards the end of the day, a familiar pattern unfolded during a few spirited laps with one of Bovensiepen’s factory hot-shoes in a Zagato prototype. The 05 GT would have unnerving stability in the big brake zones. It would then turn in beautifully for a big car, only to fall off the back of the Zagato as its nose-y balance and weight counted against it on the way to the apex. Then, once rotated, it would inexorably reel in the smaller coupé on the exit like a Lancaster bomber bearing down on a microlite. It is just monstrous and has the depth of performance and monolithic composure that tends shrink big miles with ease.

Nonetheless, one suspects those who do spend the €51,000 (circa £44,000) or so that Bovensiepen is asking for this conversion will be mainly in it for the aesthetic improvement and the chance to have a truly bespoke cabin. After all, the effects of the uplift in power will be negligible on the road, and at 2555kg the 05 GT offers no weight saving next to the standard M5 Touring. In fact it’s 5kg heavier.

It’ll be interesting to see if the 05 GT can remedy the M5’s slightly stilted B-road ride in the UK, mind. If it can, as well it might on this evidence, then along with all the other modifications, the asking price and seventh-month build time begin to look if not outright alluring then at least palatable. For Alpina's traditional customer base, added appeal comes in the form of rarity – these days the factory in Buchloe has capacity only for 100 or so of these conversions annually.

Price £144,000 (approx) Engine V8, 4395cc, twin-turbocharged, petrol, plus 195bhp AC synchronous electric motor Power 790bhp Torque 811lb ft Gearbox 8-spd automatic, 4WD Kerb weight 2555kg 0-62mph Less than 3.6sec Top speed 190mph Economy 53.3mpg CO2 124g/km Rivals Audi RS6 GT

Richard Lane

Title: Deputy road test editor

Richard is Autocar's deputy road test editor. He previously worked at Evo magazine. His role involves travelling far and wide to be among the first to drive new cars. That or heading up to Nuneaton, to fix telemetry gear to test cars at MIRA proving ground and see how faithfully they meet their makers' claims.

He's also a feature-writer for the magazine, a columnist, and can be often found on Autocar's YouTube channel.

Highlights at Autocar include a class win while driving a Bowler Defender in the British Cross Country Championship, riding shotgun with a flat-out Walter Röhrl, and setting the magazine's fastest road-test lap-time to date at the wheel of a Ferrari 296 GTB. Nursing a stricken Jeep up 2950ft to the top of a deserted Grossglockner Pass is also in the mix.