Just saw this post doing some SXR research so I figured I’d chime in. I’ve had my GroupK 850 SXR now 3yrs and it’s used very frequently, at least 3 times a week. Absolutely zero maintenance, and runs like a champ, and is stock reliable.
I wanted stock parts and I didn’t wanna mess with a $1000-$1700 rattle-trap pipe set up cracking and vibrating loose. The 850 also does not use ignition advance that the aftermarket pipe requires which probably lends itself well to longevity. I also wanted a “4 stroke” kinda pull without an erratic “on/off” hit from a pipe.
I was so happy with my SXR that I just built another 850 for my GF’s SXi Pro.
These are great reliable set ups, with great gains, keeping pretty much all your stock parts, running at stock RPMs.
If you’re like me and getting old and tired and you don’t wanna mess around with 19 brands of mismatched aftermarket crap for $5000, all bolted up for 3-4 more mph, just so you can spend your summer tweaking, tuning, and fixing rather than riding.... then the GroupK 850 is for you.
(FYI you can add a pipe to the 850 if Group K has replaced the stock sleeves.)