i believe the one on sp motorsports is also sho shop. i have the offroad one and honestly dont feel that much of a gain. im pretty sure it is because the precats are in the headers and thats what hurts flow the most. if i were you i would just save for MSDS headers that come with a a hi flow y-pipe.

FORSALE - 17" FSVT Wheels, TRubendz catback w/magnaflow muffler PM ME 02 celica GT-S 6-spd w/ TRD bodykit Greddy evoII exhaust, DC sports header Injen Short ram intake, TWM short throw shifter, 18"centerline storm wheels, Tein basic coilovers