My Stealth McLaren F1 is a premium car, race mod version of the normal McLaren F1. It's finished in matte carbon fibre weave, with a big wing and race livery stickers. It came with around 500 bhp, 1100kg, race hard tyres. I've since upgraded it to 800bhp with all mods, so it won't go as high as the Corvette ZR1 race mod for instance.
The facebook prize Jaguar XJ13 Chromeline seems to be identical to the normal XJ13, except it has a green livery with two chrome stripes over the whole car, and it has no build date listed so you can't use it in the historic A-Spec races.