I have the same sled and just put a 163x16 2 1/4" Maverick track on mine. Left the stock rear wheels on. I'm told the big wheel kit would soak up another inch. Replaced the four 8 tooth stock drivers with 2 smaller 7 tooth external drivers. Added an SLP 4" rail extension. Dropped the front suspension mount holes 1/2" and moved back 1 3/4". Had to build a new aluminum plate for the inside and outside of the tunnel. Dropped the back mount 1" and moved back 1 3/4". Had to build a 3"x4" steel plate to add on to the factory plate. Put a a 3/16" spacer, or washers, between the tunnel and the suspension mounts to spread the tunnel slightly. (Port a power is very handy for this.) You'll need to grind the chaincase bolt on the front of the tunnel, as well as the two lower bolts that hold on the fuel rack in back, to about 1/2 their original thickness. Also as xpspensive says above, Need to do something about the footwell bolts. I put in cariage bolts with the nut on the outside of the tunnel. Grind down all the rivets in the tunnel a little too. Had a local sheet metal shop build me a tunnel extension. I decided to go out the extra 6 inches needed from the original, and bring it all the way to the back of the seat. Think it was 21 inches total length. Put a 3/4" flange on the bottom of the extension for extra strength. I rode it for the first time yesterday and OMG what a difference! I need to drop my limiter strap down some to get my transfer back. But other than that it's perfect so far. I'll take some pictures this week and post.
Kevin