Porsche had somewhat an image problem with the 924. It was not seen as sporty enough. Therefore they came up with the plan to bring the car closer to racing. To achieve the homologation of a car that stood chances in racing they built 400 (actually 406) Porsche 924 Carrera GT.
Despite the fact that the car still looked pretty much like a stock 924 there were a few design changes that made the car actually looking much more serious and fast. Anatole Lapine, design chief at Porsche, came up with new rear and front (GFK) wings and a bonnet intake for the turbo intercooler. Completed with a rear spoiler and wider wheels that pretty much was it. The fact that the drag factor and the overall air resistance was as good as the one from the stock 924 must be mentioned as quite an achievement. And it made all quite a difference. Later cars, specifically the 944, re-used some of these design elements, however in a smoother and less aggressive form.
The major changes in the CGT against the stock 924 Turbo was however the engine, producing 40 extra hp and the suspension setting, as well as the brakes, sourced from the 930 Turbo.
All in all it was a convincing package and Porsche was able to sell it at roughly the price of an 8 cylinder Ferrari 308.