For normal service intervals on a road going car, the enviro 5w-40 would be a far smarter choice than the 10 tenths racing. Reason being that 10 tenths is ester based and only designed for short service intervals (one change per race day) and has a dreadfully short effective lifespan. I'm pretty sure it also doesn't meet or exceed any of the last 3 or 4 API ratings...