I have a decatted headpipe on my 2012 Street Glide. I have 3.5" Rinehart slip-ons. Like the sound but looking for more. Would it be better to get 4" Rinehart slip-ons or getting the extreme dual set-up? Is there any advantage at upgrading decatted pipe? What about performance?

 

I went from 4" Rineharts with a 2-1-2 headpipe from Fuelmoto to Rinehart classic true duals with 4" and love the sound but I did put in the high flow baffles also nice deep sound but louder. Performance wise I didn't feel it,ya might notice the difference on a Dyno sheet but doubtful in the seat of your pants.Truthfully I doubt you'd have any power loss from decatted headpipe to true duals, even on paper.Oh and I did have 3.5" Rineharts with decatted headpipe on my 09 Ultra and the 4's have a deeper mellower sound than the 3.5's. but to me just as loud.

 

This is my advice and nothing to back it up. The 4" will be deeper and probably not as loud. If you go to the true duals it will get louder and sound better in my opinion. I prefer the sound of the 4" over the 3.5" my self. The true duals will probably make you have to get a tuner as they will need more fuel down low and will pop during acceleration. Far as performance the decat will probably have little advantage down low, but after that the true duals will probably take advantage if tuned right.

 

Neither, for performance get your bike tuned. For sound, its a personal preference.