So I recently bought an 11' street glide with the 103ci motor. It had Rinehart true duals on it, screaming eagle intake, and a tune of some sort. I never ended up getting the physical tuner from the guy i bought the bike from. I want to put a Thunderheader 2-1 on the bike, but will i have to buy another tuner, or will the set up i have with the True Duals work just as well with the Thunder Header? Thanks in advance for any help!

 

You should really try hard to get the tuner from the PO. If you go ahead with the plans to swap over to the Thunderheader you'll definitely need to re-tune the ECU as you're changing the overall dynamics of the exhaust system from a dual set-up to a 2 into 1. If you were just going to another dual set-up, you would be good to go.