i blew up my y7 so now im buying a y8 off my buddy for $300....any ideas to get a pretty good gain in hp other than intake and headers

 

turbocharger ? , not much you can add to make power to those, without going extreme.

you can do:

intake
header
exhaust
VAFC tune ( if you have to stay obd2 ) or go obd1 route and tune

then

Cam ( heard good stuff with the bisimoto setups )
springs
retainers

or skip the cam/spring/retainers and go turbo, ( best option for power and fun on the cheap side )