I recommend Thunderheaders.

My thunderheaders are 2in1.

 

Looks like there is a possibility that i'll be getting a great deal on a set of v&h duals with thunderheader slipons from a member.My question is my bike only has he stage1 with heavy breather.Am i going to have to reprogram once i install this setup.what would happen if i didnt do anything once the istallation is complete.