[cummings66]

I figure I'll save money over time, not much though.

$15 visual and $20 for O2 cleaning. Take the proper courses to do both and that means that the $70 per set of doubles which need it at least once a year if not more will now cost you less. I have 2 sets of doubles which means $140 per year to maintain them to O2 clean standards (based on prices around here) and some singles. In 2 years with 6 cylinders O2 clean it will pay off. The recert is only $150 so the payoff after 3 years is easier.