Was going to use the stock exhaust and install the pro moto billet endo spark arrestor and end cap... But had some issues on the install and/or instructions were not good so not going to work. Basically cut the inner core to short and isn't going to work. Rather then spend $100 bucks for the inner core thinking about getting a slip on. So, my question is. What slip on for the 2011? Had MRD on the 07 X. Nice pipe but had issues with the spark arrestor coming out. Debating between the FMF titanium power core or pro circuit t-4. It has to have a spark arrestor and would prefer the ability to remove the spark arrestor easily for races that don't require. Sound, I like the stock sound and really don't want a super loud pipe. Yoshi looks bad@ss but the reviews say over 100db and that's too loud.