i currently have a 97 700 sx and i found a really good deal on a 2002 ac zr 900. j/w what you guys think of those sled performance and suspension wise.
ac, would be a fast sled, corner to corner i would take the 97 hands down. I really dont know what style riding you do. when i had my 97 set up, i could run with anyone or anything on the trails, but on the lake flat out those larger bore sleds would get me every time, but only after 100.
I am reasonably sure that '03 was the first year for the 900 and before that 800 was the biggest zr available.You'll undoubtably lose some reliability with the cat.
That Cat is fast, but do what Tomseal6 said, tripple pipe it, reed spacers only (the OEM reeds are best on the tripples I hear) and get it ported and Polished, oh yeah, and if ya got the money, do for an 835 big bore kit, man would that haul arse!!!!