Thanks Mr. Viper, My Sled is a 2003 viper, aggresively trail ported and one layer gasket removed ( I'm Guessing about 10 to 15 extra HP) Engine is pretty fresh only 650 miles on sled, no pipes. studded,I do primarily hard pack trail riding with some lake racing. I currently have installed 8DN20 Weights and original viper spring. I have not been able to test this setup yet since it doesn't snow or freeze in IL or WI anymore. I have lots of different rivits to go testing with now. I just want to start as close as possible and have what I need with me. Any futher suggestions would be highly appreciated.