A good set of aluminum heads, intake and a decently streetable cam will put you right at 290rwhp. To support those items, you will need at least a 65mm throttle body, bigger mass air meter, headers, high flow h-pipe, cat back, new fuel pump, bigger injectors and it really wouldn't hurt to throw in an MSD 6A ignition box with a blaster TFI coil. My car made 306rwhp naturally aspirated with all of the above mentioned parts (with the exception of the MSD and my car had a miss at the torque peak on the dyno). I had low compression for a turbo later on and a turbo specific cam as well. With more compression, better N/A cam and a proper set of headers (I had some crappy shorties), it could have made 320 to 325rwhp. The kicker is that my ported set of TFS heads, just blew your budget. How much horsepower do you want?