GT1

By 1998, the car had been renamed the TVR Speed 12 and the racing version called the Speed 12 GTS was finalising development to compete in the GT1 class races. TVR wanted to race at the 24 Hours of Le Mans, but that never happened. However, the Speed 12 GTS did manage to compete in a few races in the 1998 British GT Championship in the GT1 class, though sudden rule changes caused by advanced high-cost purpose built racers such as the Porsche 911 GT1, Nissan R390 and the Toyota GT-One and the subsequent demise of the class in other championships suddenly rendered the Speed 12 obsolete.^[3] In order that their work not go to waste, TVR immediately set about developing the road-going Speed 12, although the project would not be completed for another year.

GT2

Completed in 2000, the car was now rechristened TVR Cerbera Speed 12; it never had a true measurement of engine power output officially taken, although the original engine (which produced 800 hp according to TVR) Later confirmed to be around 840 hp. was employed yet again. The weight was kept down to 1,000 kilograms and TVR reminded people that they were making a car that they thought would beat the McLaren F1 with the words "over 240 miles per hour" mentioned on several occasions. The new car would also be built in parallel with a new race car, although TVR were forced to opt for GT2 class as the GT1 class had been dropped some years previous. The new race car managed to run for a few seasons in the British GT Championship and had some success, winning several races. It did however have problems with reliability, often leading to the car retiring from races. Meanwhile, the road car was almost ready and TVR had taken a good number of orders and deposits for it. With a price of £245,000 it would be the most expensive TVR in history.^[3]

The racing version of the engine produced approximately 675 hp (503 kW) with its power limited by the intake restrictors required by racing regulations. For the road-version of the engine, the restrictors were not needed so the engine was developed without them.

In an interview then-owner Peter Wheeler, said that TVR had tried to record the car's power on an engine dyno. The dyno was rated at 1,000 hp (746 kW) but the test resulted in its input shaft being broken. To get an approximate figure, TVR engineers tested each bank individually; the result was 480 hp (358 kW) per bank, suggesting a total rating of 960 hp (716 kW). Wheeler, no newcomer to high performance cars and an experienced racer in the TVR Tuscan Challenge, drove one of the finished prototypes home and concluded that the car was unusable on the road, in his opinion simply too powerful.^[3][4]

The deposits were returned when the production plans were cancelled. The remaining prototypes were carted around to various car shows. One by one they were dismantled and used as spares for the Speed 12 race cars still competing in the British GT championship. In August 2003 TVR placed an advert in Auto Trader for a TVR Cerbera Speed 12 registered W112 BHG. What TVR planned to do was to rebuild one of the prototypes and sell it on to an enthusiast.^[5] Buying the car was not a simple process however, and involved being personally met and vetted by Peter Wheeler himself to make sure the buyer was a suitable candidate for purchasing the car.^[5] Eventually, the deal was completed and the Speed 12 was rebuilt and handed over to its new owner. Since the original bodywork had been destroyed, TVR had to use a remaining shell from one of the GT racers. On top of that TVR did some more work on the engine and the ECU. The car featured in the May 2005 edition of the Evo magazine in which it was described as "awesome" and "terrifyingly quick".^[3] W112BHG is on display at the Lakeland Motor Museum, Backbarrow, Cumbria.

On May 20th, 2023 the originally produced Speed 12 was sold in an auction for £601,500.^[6]