How fast is directly releated to how big your checkbook is.
But most bang for the buck will probably be:
Ess Tuning
6K for an E46 3 series blower
another 4 grand for the other shit
clutch, flywheel, exhaust, random guages, labor, etc...
so roughly 10 grand to make the 3 series a fast car.
or you can buy an M3
-p