As far as the Nasty PM,s.Guys this is a Hobby for me. I dont profit from any sell. I however have an advantage as I do most the Doo BB builds in the area and tune a/test.I get to see and run them all.Builders rarely test other builders motors much and focus on what they sell. I have had 4 sets of cylinders on the bench from different builders at one time and you can quickly see who puts the effort in the porting. They all have a difference in opinions on porting specs however some dont even spend the time to remove the huge casting flaws and this is just BS.These are chunks of aluminum extending into the cylinder ports-Porting 101.Your not getting what you paid for. I also see the shortfalls with each individual part and mix and match then test . I have found what I feel is the best squish and compressions/ motor setup for Altitude motors only.I Do allot with clutch testing as well ,Tom,s Snowmobile has been very innovative with some clutching enhancement parts and Ive learned allot from Tom, testing ,trial and error,but only on these mod motors.Its interesting talking with Tom as he constantly enhancing even recent products,He doesn't stop just because he found a successful modification and keeps striving for perfection.I dont try to talk up something just because I own it, I have the option to run anything i wish and have most all the components here.There are really good builders who listen to the problems and change design to run with todays fuels.Then there are others who will not.However its all these options that keeps the sport interesting,I constantly talk with riders who argue how great their setup is however thats all they know and until you explore all the options,Oh well.Remember ,One sled length makes for a Winner,This imply s theres a looser,that could be you!