I have spec 1 r33 gts. I have hks duel dragger exhust, de cat, large turbo downpipe and irridum sparkies, also slight mis fire a 5000rpm. Hve been told this is because of the mods iv don to a otherwise standard gts and it could have something to do with the coil packs. I want more power!! 4oohp and how to get it with the intention of more power in the future. Any help and oppinions would be great. Im new to the skyline so not sure whitch way to go HELP!!!