I've got an 01 700 RMK with a 144" I would like to get more floatation out of it and was wondering is it possible to put a 151 or 155" under it without much modification? And if so do you feel it's worth the expense and time.

Just need a longer set of rails and possibly a new rear mounting bracket. You'd have to go 151. Can't put a 155 under there since it's a different pitch track.

Why couldn't you do a 155? Go get some drivers, they are only about another $100 and the 151s are starting to get outdated. All the manufacturers are going to different pitches so if you need a track in the future it will be easier to find one. Either way good luck, and make sure you have enough tunnel clearance for your lug height.

just go to tracksusa.com and pick up a set of rail extensions/tunnel extension/and track in a package deal, they seem to have the best prices and i know they have fast shipping