In the premium lounge you can drive with the gr.3 and gr.b road cars, Ferrari 512 BB, Lamborghini diablo GT, McLaren F1 and the Toyota 2000gt.
In the midship challenge the diablo and F1 are also added.
From now on I will be too lazy to as the obvious new cars.
FR challenge: I believe the Toyota 86 GRMN was missing, same could be said about the safety cars.
Actually, it could have been the boxer challenge where it was missing from.
Although I have pretty much a photographic memory, it too has its limits.
What I am saying though is that a lot more cars you would expect to be available in GT league are available right now. This means that all cars from all groups (gr.x included) are available, if they meet the "homologation requirements"
TL;DR: more cars available in GT league. Don't know which cars exactly because I am only 90% sure what has changed.
P.s. something that hasn't changed (frustratingly enough) is the credit limit. It is still 20.000.000/2.000.000.000