[RABAUKE]

A car engine is an air pump, the more air/fuel you can get through it the more performance you get. It needs to breath, so intake, exhaust and timing. This can be achieved by a number of things. Throttle body or carb, headers, valves and timing will do that. Tires are a handling issue as is suspension, firmer shocks, stickier tires and better breaks all will help with performance, but you really want to get the engine to breathe, this is a bigger issue and more easily addressed with older cars but will get you lots of bang for the buck.