You might want to hit one of the sled forums like Snowest.
http://www.snowest.com/forum/ Tons of info. I drag raced two strokes for years and I can tell you that an EGT gauge was the difference between a burnt piston or a successful weekend. I believe the units I used were from Westach. You'll read how the EGT or an AFR gauge is hogwash because the probe gets contaminated from the two-stroke mixture. That's BS! Check out small two-stroke aircraft and tell me what they use to monitor exhaust temps. EGT's!
Anywhoo; an EGT will save you when modding a two stroke. Learn how to read it and what exhaust temps are acceptable at 1/8 . 1/4, 1/2, 3/4, and WOT. The new digital ones come with warning lights to alert you of a lean condition. Did you know that most owners burn up a two stroke at cruise and not WOT? Yup. That's where you spend the majority of riding time also.
Also; to read a two stroke plug properly; you need to do a throttle chop. Let's say that you want to test your tune at 1/2 throttle. You would take off and hold her at 1/2 throttle for a short distance. You then hit the kill switch while holding her at 1/2 throttle until she comes to a dead stop. Now read your plug immediately. If you wait an hour or day to read the plug; the color will change and give a false reading.
Also; to get the best bang for your buck after adding any mods to a sled; you must dial in the clutch. Even a stock sled can benefit from a clutch kit. The factory sets them up generically and tries to soften the holeshot for liability reasons. Toss in a proper clutch kit and belt and that sled will really come alive.
Here's some pics of my old racers for your entertainment pleasure: (Click on pics for a larger view)
I sold this '99 to my business partner Dennis so it doesn't list the quad as mine. The first pic shows the changes in graphics he made at his house. The remainder of pics are in my driveway during build. I ran a successful campaign on alcohol without a glitch thanks to Lectron Carbs and Westach EGT.
http://www.angelfire.com/or/Gurgorama/readers/dennis2.htmlThis bike started life as a 4x4 Polaris! I built the first Polaris 400 stroker engine ever built for this bike. I was told it could never be done.
http://www.angelfire.com/or/Gurgorama/readers/eric3.htmlMy first and last racer. This is a '98 that I purchased new when working as a Polaris technician. It became so competitive in sand drags that the other racers with more cc's whined that I should be in a separate class. The tuned auto clutch gave me quite the advantage despite what folks will say about manual bikes being superior. Nothing holeshots like a tuned sled clutch.
http://www.angelfire.com/or/Gurgorama/readers/eric1.html