Way to many compromises,I would just pick up one of the loaded stupid cheap
B5ms as a dirt car and get a B6 for carpet.
Good answer. I am in a similar situation. I decided on the B6 due to the fact that I would run a laydown transmission anyway. It looks as though Spencer Rivkin is running his B6 versus the B6D. He has done a few things like shock tower changes and the front arm changes, but he is primarily stuck with the car that he first got which was the B6. As he is the world champion his setup works for me.