I've always preferred the c6tgc over the OD plugs, but out of the OD plugs I think the 277t is the best. The 288t is good too, but it's a little cooler and probably closer to a c7tgc. I don't think they make the 99 anymore, I could be wrong but amain doesn't carry it anymore I believe the v2 plugs are the only ones OD is making these days.