I'm in a different boat.. I've owned both and I didn't like the delivery of the T5's..They wer eon the bike when i bought it and I sold them within the first month.. I perfered my DMC 916's over my T5's.. The plugs actually are easy once you figure it out.. You stick your arm in the opening in the loop they make and there is plenty of room.. Besides the fitment(which the T5's weren't that great either) I really liked my CPI's.. It isn't a thorough comparison as my T5's were on a stock motor and my CPI's were on a dune port motor but i really liked my CPI's alot better than my T5's.. This is just my opinion of course but i have owned Shearer, CPI, DMC 916's, LRD, FMF and T5's..