just a very general statement as I has exactly the same thoughts after my first autocrosses:
It's not the car, the tires, or the suspension, it's the driver
As long as you can easily find someone at the same event that does the same Auto-X course in the same car 5 sec faster or a lap at the track event 15 ~ 30 sec faster than you, don't bother investing in expensive new hardware.
When your driving skills are finally honed enough (after a few years) that you reach the limit of what your car can provide, then think of stickier tires, bigger rims, PSS9 suspension, chip tuning etc. (or a GT3 RS
)
I am not trying to be arrogant here, as I myself am still at the beginning of this learning curve. I rather invest all the money I save by NOT buying rims/tires etc. to buy me more seat time at Auto-X and DE/TT events - Buttonwillow here I come
