The engineers who designed the Rush line of slip-ons and full header exhaust systems really new what they were doing. Not only do they offer a richer sound than that of the current SE pipes, but their focus on performance should help carry this company through these tough economic times for the industry.The Rush slip-ons you spoke of have a simple yet highly effective reversion bar welded across the diameter of the pipe near the end. This bar breaks up the sonic pulses created on the exhaust stroke, preventing over-scavenging of the combustion chamber during valve overlap prior to the intake stroke. (otherwise known as back pressure) You have made a good choice, I have tuned several late model sportsters (on the dyno)with these pipes, and have achieved very good results.