i wouldnt go the 3 speed route, i would just stick with 2 speed. i switched one of my Xl's to 2 speed and like it better. better bashing, less headaches
also, if you want wider stance you can use Flux axles with offset wheel/tire combo, they arent extended like the xl axles. also, i would suggest the 29/9 differentials if you dont have them already they will hold up better.
i converted an x to Xl a few months back, and when i was all done, it would have been cheaper just to buy an XL roller(extended TVP,s, 29/9 shimmed diffs w/ 11mm outdrive cups,11mm dogbones,extended rear dogbone,3 speed tranny w/52t hardened slipper,and 11mm cupped long axles w/the purple extenders) off epig.if i had been able to buy all the parts from 1 merchant, it would have been a wash, but the shipping killed the deal