Excellent info. I'm also preparing to order an insert from RMATVMC, but I may even go to the next step down in volume. I'll reply back with which direction I ultimately go, as well as what happens with jetting and performance post-install.

DJ, the two quite cores are just about the same besides a few less holes drilled in the "trail-friendly" version, the tip is turned-down more, and a sound deflection ring of some sort. This might get you to even be able to run "super-stealth". I know my exhaust note now is very, very pleasing to the ears from what it was. Heck, with that installed you might not even need to re-jet, either. Keep us updated...

Kirk

The "trail-friendly" unit was just ordered, along with some minor accessories. I won't touch jetting (though I want to) until after the insert install.

BTW, for those interested, I did measurements on the inlet and mount-points for the muffler...it looks to be a direct-swap for any aftermarket KTM 4-stroke "slip on" for the 2014-2016 KTM's. It seems that aftermarket support/availability may be on our side, though at "Euro-bike" prices for the moment.

I'm still around, been riding bike a lot with no complaints. Stock chain would probably be the only if I did. Have been watching the jetting, went back to 0.052" main jet and the needle clip on the very bottom. Haven't checked plug yet, but it does run better with cooler temps. Plug showed very lean with needle clip in middle and 0.049" main jet. I will be dual sporting this bike after I get some bills paid off. Keep y'all posted. Kirk

I have a Orion RXB250L. Anyone have a suggestion for installing a spark arrestor? I'm thinking of entering into a motorcycle race that requires bikes to have a spark arrestor installed. Naturally, I want to do this on the cheap.

The LEXX DB-killer insert counts, even if it not the trail-saver version. Replacing the muffler with the complete LEXX muffler and insert pair will get you a USFS tag, I believe. (confident but not positive).