Hey people,
I new here but have visited this forum many times in the past and found it very informative. Now to the Question at hand. I have a 2018 FLHCS 114, I didn't like the sound of the factory exhaust so decided to purchase a set of Vince & Hines twin slash 3" slip on and I couldn't believe the sound and performance increase. However I was informed that I needed to have it tuned in order to retain my 2 yr. warrantee. I purchased the Eagle screamer se pro street tuner and had my local Harley dealer install the recommended updates to the ecm. After the service the bike does not seen to have as much pep, don't get me wrong this thing is fast and has plenty of torx but not like it did after spending an additional $399. for the tune kit and $65. for Harley to install the (up date). Again its still fast and all but just trying to figure out why the loose of umph.

Thanks for any help or thoughts.

 

 

I have slip ons on my m8 and didn't need any tuning just like the twin cams. As long as they are epa compliant, slip ons alone should not cause you any warranty issues.