The R8 race has been pushed back.
This weeks race is going to be another challenge race with winner takes all stakes. Every person can spend no more than $150,000 on the cost of their car and its modifications. So that $150k INCLUDES purchase price of the car, and you cant use a car you already have, must be bought.
To keep people from cheating the cars can be examined in the community tab under the users profile. Just make sure you favorite the car your running and click "share with friends." That way we can look at it and its mods.