hey guys, I have a 98 with a 144 2 inch track with elkholm tunnel, 9 tooth drive, 20 40 gears. I added mid and tip weight to the stock weight which took it up to 58 grams total. it helped a little. running 8300 rpm. stock springs, running tight secondary ,stock 47.5 helix and green spring. servo and power valves work, and set up proper.stock exaust,although I do have the aaens for it.ya got to help me set this thing up! a stock rmk 600 polaris is neck to neck and takes it on the top . talk about embarrassing !I do lots of powder and trail agressive once and a while we get to lake race it.thanks guys, this machine should slaughter that sled!