Personaly I think they are great. I have them in all my motors and get years of service. BUT, if your motor only turns 5000 or so now, they wont magicaly make it turn 6000. The transition between rpm ranges will be slightly smoother but thats about it and perhaps a little better idle.<br /><br />Good luck!
As Jb said..Dont waist your money! If you dont do it right you will "Lean Seize" your engine and spend more money..Not alot of difference. Spend your money on toys and steaks! My thoughts only.