The GT2 race car will be based on the ZR1. At least in looks.
Hydroformed aluminum frame made by Dana with steel roll cage. Still developed by Pratt & Miller.
6.0L "destroked" V8.
From 2010, 5.5L or smaller V8. LS3 head and block. ~500hp.
Apparently Jaguar is looking to enter its XK race car into the GT2 series. They already have the GT3 race car. It shouldn't be too much of a stretch.