That is a strong engine but there are some things that need to be done to insure its reliability. As sschne62 states I would do some reading over in the Machz section of Dootalk. The biggest killer of these engines is fuel pressure problems if the low pressure fuel pump starts to fail it will lean out the engine and cause a meltdown. Not trying to scare you away from the Machz as it is a great running sled it just needs a few tweaks to give it the dependability you want.
Ski-Doo -"They said it was impossible to break 3pounds per horsepower. Thats exactly why we did it!"
15 Renegade XRS 800 etec
10 Ski Doo MXZ X 600Etec