A single car - the 911 GT1-98 Straßenversion - was built in 1998 to homologate the all-new racing version under the new FIA regulations. The engine had to be slightly de-tuned to meet European emissions laws, although its 400 kW (544 PS; 536 hp) at 7,200 rpm and 600 N⋅m (443 lb⋅ft) of torque at 4,250 rpm proved to be more than adequate; the car could accelerate to 100 km/h (62 mph) from a standstill in 3.6 seconds on its way to a top speed of 193 mph.
Homologated roadgoing version of the ’97 911 GT1 Evolution racer costing $890,805 upon release. Twin-turbochargers were fitted to the M96/80 engine, which had water-cooled cylinder heads. Apparent from the front and rear lights, the GT1 shares many components with its series production counterparts, but puts them together in a more competitive way. Gone is the rear engine layout which isn't suitable for prototype GT racing, the GT1's turbocharged flat-six engine sits in front of the rear axle and is supported by chassis tubes instead of the typical 911 rear sub frame.
To comply with homologation requirements, Porsche built two street versions of their 1996 Le Mans contender. These pre-production cars are essentially the same as the race version without all the safety equipment, a higher ride height and more interior amenities. The two street versions were actually built in 1995 as 1996 model year cars. The engines were slightly detuned from 600 bhp to 544 and the gear ratios were changed.
The 1998 GT1 car was a totally rethink and vast upgrade versus the prior year car. 1998 Le Mans 24-hour race In the 1998 jubilee year, the Porsche team celebrated its 16th overall victory in Le Mans with a double win for the 911 GT1 98. On 6th/7th June, the winning car was driven by Laurent Aiello, Allan McNish and Stéphane Ortelli. It was almost 50 years to the day on which the first Porsche sports car saw the light of day.
Towards the end of the 1996 season, Porsche made revisions to the 911 GT1 in preparation for the 1997 season. The front end of the car was revised including new bodywork which featured headlamps that previewed the all-new generation of the (996) Porsche 911 which would be unveiled in 1997. It had the same engine as the previous version, but new aerodynamic elements allowed the 1997 version to be considerably faster than the 1996 version. At Le Mans the works cars led the race but did not last the full distance; a privately entered 1996 specification GT1 managed 5th overall and third in its class.
In spite of its 911 moniker, the car actually had very little in common with the 911 of the time, only sharing the front and rear headlamps with the production sports car. Designed and developed to compete in the GT1 class of sportscar racing, which also required a street-legal version for homologation purposes. It was powered by a twin-turbo flat 6 that was good for 600 bhp. The 1996 911 GT1 clocked at a top speed of exactly 330 km/h (205 mph) on the legendary Mulsanne Straight.