For sure a tough spot to be in, for me I would sell everything and not worry the 18 won't disappoint, My mod days are behind me mainly because the sleds don't need it. I still do improvements like steering bushing,manual chain tensioner etc but nothing major. My riding time is limited and if something should need replacing it is nice to be able to go with the OEM and get back on the snow quickly. Years ago mods were a way for life, but they were needed to make the sled perform. The new sleds are so much better and purpose built they just work. You may still find things you want to change but mostly it's a personal preference. A properly setup 18 MC will push you as a rider, a large majority of mountain sleds (all brands) aren't being ridden to their potential.