If you are after a air shock then go for SX or 2010Enduro!!! They feel really alike but shorter travel
SXT should go with 170mm travel forks, its no point to go longer travel coz its a FR bike, longer travel will mess up the geometry making the bike unbalance and give lesser control
BTW you can run air shock but just u got to find the exact same e2e and stroke length shock which they might not avilable aftermarket(not too sure gotta check with fox)