I have an 04 ultra classic screamin eagle and i am replacing the 3 " pipes with 4" vance hines double slash cuts. Do i also need to add a tuner if this is the only mod i'm making? if so recommendations from those in the know..

 

Conventional thinking is if you leave the air cleaner stock then you wont need to do anything else.....I like to look at the plug and exhaust coloring to determine lean/richness, many do not.

 

If not changing the air cleaner your fine