How much top end do you want, and what r u getting now? There really is NO need to change gears unless you change tracks and secondary clutch. The gain with any gear wil be little to none in stock form. The M6,7,8,10 are all geared to run in a respective 1:1 ratio or less which is around 50-60 mph, after that you are in the very ineffcient OD. The top speed for all of these machines at thier respective operating rpm is approxamately 100 mph. This CANNOT be achieved unless on a run stand, or going DOWN HILL on ice or similar resistance surface. Keep in mind after 80 mph, you can start to expect light to severe damage with track and skidframe components, it will depend on how your suspension is adjusted at time. Things like track stab,clips flying off, blown thru hyfax( in just one pass) lugs being ripped off completely, IS POSSIBLE or LIKELY. Alot of track sag, good for MTN riding, catastrophic on a high speed run. On a run stand at the hillcross, an entire rug destroyed and sent out back about 40'. the extrovert drivers will tuck the rug under and into the rail caps and this is where most damge begins. A very good holeshot rippin setup for an M8, is a AC y/g,red, or new gold primary spring. Weights will have to be adjusted for your Alt. secondarybelow 3K, 48/44-36 or 44-36 full progressive ODS can get you both from dalton, a spring in the 150-280 range for the secondary and 036 belt or 046, if an 060 belt is used a lower 125-225 spring can be used, Your weight and snow conditions will determine exactly what spring is best for you, as the load a 2.5 lug track adds to a motor is WAY more and sensitive to clutching than a short lug. Springs are cheaper than weights and new helixes, and can make wonders of what else you might have in your box. Above 3K a 46/42-36 or a 44-36 FP is better. A D&D shift assist is a must for smoother shifting and CONSISTENT results. Also shims of any kind to adjust spring pressures with new helixes are a good idea to make quick rate changes, .25 is about 30 lbs on the AC orange spring.