So as the title says if you had $500 to spend what would you get. You already have an intake, headers, underdrive pulleys and full exhaust. what else would you get??
Save longer. Assuming you want power mods now is the time when you save or else you will piss all your money away on mods you will end up replacing anyways. Save a couple thousand and get a nice hci setup or a used s-trim.