Are you going to concentrate solely on the racing world? If so in this area - you best be prepared to not make a whole lot of cash. There are 5 or 6 major vendors who have the NASCAR market tied up (remember there is a finite number of cars available) and any of the lesser teams or lower classs race series will end up trying to barter your work for ad space or draw you out past 180 days to get paid.
I don't do any work for the Speedway anymore because I am not a bank and can't float that kind of cash anymore for as long as they will take to pay.
You are going up against Mortorsports Designs, ProCal, Decal Source, Red Eye Designs and several other smaller places around here.
Anyway, logo is fine and good luck.