Snowman 72
For most bang for your buck, just do the track change. I have two sleds, both 98 Vmax 700's. One has the standard Yamaha 3/4" track, the other has the Yamaha optional 1.5" track and wider skis.
On trail which is about 90% of the time, there is no difference in hyfax wear. Much better on-trail traction both accelerating and braking with the taller track, will never go back to a short lug height track on future sleds.
Off trail, which is one weekend a year at the Ride-In, they are two completely different sleds. You will be completely amazed at how much difference the deeper track makes in deep snow traction. I am able to try hill climbs and deeper snow riding now that I wouldn't have even dreamed of before