I really wish I would have done a before and after weight when mine went on a diet, but here is what I did, with manufacturer "claimed" weights.
Skid - Fabcraft (loss of about 30-35 lbs) Their 144 skid claims to weigh 46 lbs and a stock one I believe is in the 75-80 lb range
Seat - Boss (loss of about 9 lbs) Stock is 16 lbs and Boss is 7lbs
Front suspension - Timbersled Barkbuster (loss of about 10 lbs)
Track - A/C 156 camo from the Yoko 141. No clue, maybe lost a few lbs, but probably a wash. I think the 156 is in the 55-60 lb range.
Other items that will lighten things up are:
Hood - Stock one is around 17 lbs, aftermarket lexan is around 7-8lbs
Can - Not sure on stock weight, SLP for example claims 6 1/2 lbs weight savings
If your budget is endless, as snowdad alluded to, you could do a whole boatload of carbon fiber parts replacements. But at that point, it'd probably be cheaper and easier to just buy a new RMK or M.
There are other little things here and there that will save a few pounds, but that's the bulk of it. I'm guessing I lost, realistically 45-50 lbs.