Want to know the most cost effective way to make most cars quicker around the track, or anywhere else ??
Improve the driver. Yes..... Enrol in some driver training courses, the best $$$ you will ever spend. Might even save your life on the street.
Seriously though - I am not suggesting that you are a bad driver, just that there is not much point spending too much on a car until the driver has the skill to get the most out of it.
Just my two cents worth
PB