in think the best modification you can do for your car is the driver...take some schools and get practice...most schools prefer the driver to start out with a stock car (as it is factory tuned for understeer and has a much clearer limit so the instructor can fine tune the students skills). Starting with a highly modified car makes it harder as the stucent must know how to tune the suspension of his car and that means lots of trial and error as every car is different (hence the preference for a non modified car)