I'm looking at purchasing a new Niner Air9 RDO soon and am trying to decide which build to go with, either the 2 or 3 star build with the Reba fork. The cost difference for me between the 2 star build and the 3 star build is 900 bucks.

It looks like the parts difference comes down to -

full XT group (ice tech pads and rotors), carbon bars and seatpost, Race Face Turbine crank, and Stan's Neo/ZTR Arch MK3 wheels for the 3 star build.

The 2 star build has Niner's alloy wheelset, alloy bar and seatpost, Race Face Aeffect crank and a full SLX group instead.

So, I'd like to hear any opinions on this. Would it be worth the 900 bucks for that upgrade or is the SLX bike the better buy? I haven't used either of these two groupsets to get a feel, but my current full suspension bike has full 10 speed XT and it is pretty sweet. I cannot afford the upgrade for the 4 star build with the carbon wheels and fox fork, so it is between these two builds. Any advice would be appreciated.