underdrive lightweight pulley

is it a good idea to put a lightweight underdrive pulley on an 00 civic ex? will i gain anything? thanx

you can gain uip to 5 hp if your lucky, you can get even more back if you take off all the belts you dont need to, like ac and power steering, jsut leave the alternator belt on and youll have a few more, becasue the motor will be working less hard on turning that crank, and harder on turning the wheels