"Best thing we ever did with those S-chassis Summits was take off the DPM and straight jet them to your elevation. Made a big difference in power."
Agreed! But on the '96 they had HAC. A MUCH simpler system, and easy to take off. I replied in a post detailing a step-by-step procedure for removing it. It WILL make the sled run much crisper, and save you money on plugs! lol
As for suspension, the stock summit SC-10 leaves ALOT to be desired. The weight transfer alone is enough to scare the crap out of a newbe. Don't waste your time looking for better shocks. Money better spent would be hunting around for a newer style skid-frame. In one of my sleds, I installed a (gasp!) Arctic-Crap skid from a '00 600 Mountain Cat. Night and day difference. I also installed a good set of front shocks. LOVE the suspension on that sled now. It just BEGS to be airborne...
For a bigger lug track, you are left with one of two options-
Hard way - find a drop and roll kit. (good luck, hard to find as of late) royal pain-in-the-butt to install, but you get to keep the factory 9-tooth drivers, and get a marginally better angle of attack.
Easy way - go to 8-tooth drivers. Only problem with that, is the smaller drivers have a habit of racheting pretty bad under load. You can tighten the track to compensate, but you lose performance. An 8-tooth extrovert would probably be your best bet if you install a fully-clipped track.