Interesting that you all say no need for fuel management for the slip-ons. I was told by local HD mechanic (and friend so he was not trying to sell me anything) that if you step up from the stock 1 3/4 inch baffle, you would need the managment due to back pressure changes and the fact that the bikes come pretty lean from the factory anyway due to EPA standards.
I don't know the answer just repeating what I was told.

 

IMHO you need a fuel manager even if you leave it stock. I'm running my slipons w/o a fuel manager right now cause my dfo died. I changed back to the stock a/c to try and keep it from being to lean, but I can tell that it is running lean from the slight surge I get and the frosty white plugs. I wouldn't run it this way for an extended period of time, but the weather has been cool and I haven't been riding much. The big sucker goes back on along with a new PCIII after Christmas.

 

To the original thread post: you can get by with just slip-ons, assuming you have a closed-loop bike, but any breathing changes, in or out, really benefit from a reassignment of some values in the EFI programming. If you don't want to go that route, a piggyback device that'll let you tune each cylinder individually is the next best choice.

Assuming you have a closed-loop bike, especially, and even if not, probably, you'll be smiles ahead to spring extra over the PC-III for the TTS tuning system. Trust me, I've done both.

 

A book could be written on this topic, but this post best summarizes the answer.

 

Slip-ons and ride!