Just finished putting a 13 belt drive on my 12 Pro. It took a little cutting and grinding to get the backing plate to fit, but besides that it mounted right where the 12 backing plate mounts. I've also heard horror stories about getting your belt back on without the Polaris alignment tool. I just rolled mine back on like you would a chain on a bike. I put the belt on the top pulley, held it on the front of the bottom pulley, and had a friend rotate the track. Once you get the belt all the way around the bottom pulley, just keep pushing in on the top pulley and rotating the track. Eventually it will roll into place. It worked pretty slick.