I fitted splitfires to my R33 yesterday, i can run higher boost now without the flat spots at 4500 rpm now it revs all the way to 7000 without a cough n fart. I have also been using NGK bcpr6 copper plugs at 0.8 gap. I found that all the stock coilpacks were shorting through the plastic jacket, you could see the burn marks obviously. Its just a pitty splitfires are so stuffen exspensive.