why the fuck would you put a 20 into a 31
rb30's are way better, ive had a friend go through 2 20's and he decided on a 30 since they win
also have another friend with rb20deTT s13 and rb30de+T 31's with decent turbo shit over it.
Cheap track car would be r31, rb30de+t
look at fankis 31 its a standard 30de then +t and it skids like a dream