I have just bought a TT for the race in the b-class and now need an R8 for B-8. What race is good for money, so far it is B-1 but that will take some time still, the R8 is around 16,000,000 credits!
Yep, once you have a lap your happy with you can quit and you'll get the cash. You can keep going untlil the timer stops which is good if your more interested in the times than the credits but you don't have to.