Eagle2000GT

For a fun daily driver in the 250-270 rwhp range (that's 275-300 bhp at the crank) that actually feels like its faster the above recommendation are very good. 4.10 gears, tb/plenum, 93 octane tune (tuner needed to correct your speedometer for the gears). Depending upon the type of inspection you have maybe an off-road mid-pipe for the exhaust.

If you're wanting more then I recommend you forego the above mods and save your money for a blower. A centrifical supercharger (Mongoose kit is $3,900 plus installation) will jump a completely stock motor to 350 rwhp (approx. 400 bhp at the crank).

You can also use nitrous if there is a convienent fill station nearby.

Edit: With the gear you may also have to replace your lower control arms to help the car get a little more traction. Otherwise, you will be spinning your tires a lot (which can be fun).