My 19 sleds have been 500% better than my 17/18 sleds.
17 154/165. 200 miles before belts are worn beyond deflection or blown. Every 5 minutes of riding had to throw snow on clutches to cool them down. Smelled burning belts all the time. Coming off 16 sleds with DJ clutches with 1600 miles per belt, I hated the sleds so much that I sold my 165 in January.
18 175/154 Freeride. Better, gave up on messing with it and just rode them with worn belts, but only put 700 miles on between the two. Was kinda bummed on sledding after the 17/18 sleds. Loved the chassis though, over the XM models.
19 175 Summit, 154 FR. 180 miles on Summit, 150 on Freeride. Haven't looked at, smelled, worried about the clutches or belt on either. No loss of performance. These things RIP. Hot or cold, performance is the same. Haven't even checked deflection. I AM using the updated belt, I sold the stockers.
The 175 does want to go faster, it must be geared down over the 154. 175 on the lake in 5 inches of fresh is still pulling hard at 73mph, the 154 pulls 73 but doesn't like it. But performance where it counts is still spot on.
Happy New Years!