Between the 2 I would get the 18 cat. 1600 miles on a turbo axys would scare me. Most turbo set ups I see for sale around 500 miles for $9-10k. I had a 17 axys with raptor shocks and k mod a arms, was absolutely in love with it. Decided I "needed" a turbo, went with the exact same "you only live once." All that happened is I spent most my time trenching or wheeling, was actually worse at tree riding and blew belts and hated my sled. Realised I don't need $18k into a sled. Some how luckily sold it for $14k and spent $5700 on a 18 cat with higher miles but in immaculate condition and I will throw a top end in. Any way in summary
17 axys w/out turbo was best, raptor shocks were awesome
17 axys with turbo, fun at times but mostly a waste of money and down time
18 cat. Meh, still miss my axys but I am good with it for the cost and reliability. The 18 is way better than the 16 I have rode. But even though I own one, you will never try and tell me it tree rides or sidehills better than an axys. I miss my axys if you can't tell