who here has replaced them and what kind of difference should i expect? I only have 39k mi. but I keep hearing replace them, I run 12.90 with radials 105 mi. but I will say I feel a BIG drop in power at the last couple of hundred RPM's in 1st espesialy the exsaust is no cat, flowmasters and 2and a halfs after the y so there could be some im provement there that might help high RPM's, but other wise my other add ons are red 93 street, adjustable fpr, xp pump cold air and breathers. Thats about it any info would help...... ps just want to know I'm problebly going to change them anyway, I just want to here what you all think tnx for your time eric smith 86 gn