I put Skinz washers in my rear skid for this season . I ride 2016 t3 163 . My opinion is that it doesn't help with rear of sled washing out in a side hill situation . I wouldn't waste your time or money on locking it out. The true fix to washing out is suspension set up .
Reason why I say stiff front shocks , is because he is running factory shocks , with sway bar disconnected . When your side hilling and you have all the weight on one ski , and your ski shocks are soft , you will be so far into the stoke that you won't have any shock travel left for when u run...
I ran bikeman exhaust om my 2014 xm and had lots of issues . I would definetly try it with factory exhaust back on . I switched my bikeman out for slp , and never had another issue . seems like the etec only likes slp or mbrp . Running just mbrp can on my 2016 t3 and no issues