have a 98 cobra with 22k on clock. upgrades include long tubes, x pipe, upper/lower controls arms, 411, 2 1/2 cat back, off road pipe, cold air, accufab tb, msd wires, steeda shifter, lowered 1.5, tubular k with arms, front coil0vers. want to add more power should i add vortech or stay NA?? plz help. thanks. rob.