Best bang for the buck, at least for my car, Gut the precats and install mil eliminators, Sho shop y pipe, remove resonator, port maf, port and remove the back side of the TB butterfly bar, K&N cone air filter or equivalent, and maybe try the IAT resistor mod. This has been great for my car with no driveability issues. All cars react differently. The only real cost is the y pipe, air filter and time. $450 and about 10-15 fwhp if you are lucky.
