So I went ahead and ordered and received a clutch kit from SpeedWerx for my 2013 550 with 27" Zilla's.
The kit comes with stiffer springs that raise the wet clutch engagement rpms.. I believe it's to 2400, a .60 primary shim and smaller diameter rollers 4-20grams and 4-15grams. And it contained a detailed set of instructions as well with a few tuning option recommendations, better mid-top end vice bottom-mid range and what to install to achieve either. Well during the disassembly I did have a issue getting off the primary nut but we did get it off. When I took off the CVT cover I noticed how high the belt was already riding on the secondary. (1st Pic) It's basically flush with the outer rim (maybe has 1/16th). So, I'm not sure if I'll be able to use both the rollers and the shim and not have the belt ride too high in the 2ndary. 2nd pic is of the belt and how it rides in the secondary with the smaller diameter rollers AND the 60thousands shim installed in the primary. The secondary has been re-clocked to B3. I did not install the stiffer wet clutch springs though. After talking with a few people and a lot of interweb reading, most of my riding is on trails under 40mph's so I wanted to se how all the items I installed performed before I delved into the wet clutch. Tonight after I clean up the mess I created in my garage, I'll temporarily install the cover and foot rest any run up and down the street a few times to see how the kit parts I installed perform. Oh yeah... after I set the belt, I did start it up and made sure the pri & sec moved as they should. And I did not hear or see any part of the belt hitting the housing. And the belt (1500miles) was in really good shape, so I just washed it and re-installed.

 

Post up your results. Curious as to what your top speed is with the 550. If my old 2001 500 manual shift ever dies, I'm probably going to look at a 550 TRV, I really like my Cat! Best top speed on level road with 30" tires is 55 mph (gps). Takes a long long time to go from 50 to 55. 6,600 miles on original wet clutch, seems to work perfect.

 

Sure will hydrex... once I get it back to the property. But I didn't install the kit for a better top speed. I did it for better low and mid grunt.So,

I put on the CVT cover with 3 screws, put the floorboard support on and took it down the street! No rubs, knocks or noises! And just from 3 little runs up and down the street.... NICE! No full throttle cause it was only 1/4 way buttoned up and only about 1/2 throttle but I could tell the launch was ALOT harder than before the clutch mods... VERY happy with just the initial test. Finished buttoning her all up, now on to oil/oil filter/diff fluid/spark plug and air filter maintenance and while the diff fluid is drained removing the front right shaft and replacing a boot band. I can't wait to get it back in the woods!