Technicians I have discussed this with say that Rineharts actually decrease performance! But they sound OK.
i put a k+n filter in and had to fit a power commander, no way should you bolt pipes like this straight on as they will run far to lean to the point of causing damage. fitted correctly there is no decrease in power anywhere in the rev range, pulls much stronger mid range if anything. really struggle to understand how any performance pipe (fitted correctly) can decrease power as the standard pipes strangle everything the engine is trying to produce so that the bike meets noise levels, emmisions etc.try feeling the weight of the standard cans and then try to imagine how much shit is inside clogging everything up to make them that heavy. air flow on new bikes is generally restricted as well for the same reasons.this is the same with other makes not just harley
rinehart with a serious reputation and background in nascar racing exhausts do the r+d then have bub make the pipes. they would look like clowns with all that experience producing a pipe with less power than stock and surely in a country like the states someone would just sue their ass for bullshitting. i would assume this would be the case regardless of who makes the exhaust vance + hines, screaming eagle etc it should do like it says on the packet. those pipes you got your eye on look quite nice Mr bear but i don't think my bike looks like a road king either, maybe that was another technician quote
at the end of the day loud pipes save lives