I think you should rethink the starting procedure, cause a flying lap with a pace car and a green light is a bit different. After pace car is gone, pole sitter controls the field, and accelerates when he wants. Also no overtaking until the start/finish line. Just like a standard flying start.
Personally I don't really like multiclass racing since it kinda splits the grid in half. Like let's say you have 30 cars on the grid, 15 GT1 and 15 GT2. In this case you cant really compete with 30, but with 15 cars. Less cars to compete with means less action. The LX4 could provide excellent battles since it's not that hard to drive, but can be kind of challenging.