EFI is the only way to go IMOA. I have two sleds with EFI systems. Over 2k in mountain miles in harsh -26 F weather with snow and ice and not one problem also they will lean you out on a 90deg day and give you much more power than a carb and on a cold day richen up for lots of power and no lean spots. Point them downhill or tip them over and come back the next day and 2-3 pulls on the rope and they fire right up. Also on average in a full day they use 2-4 Gal less of gas than the old carb sleds of the same CC size with 12Gal tanks. Once in a great-great wile someone will lose a sensor but almost all the time they will just go into limp mode and you can still get out on 50% power. Also there are not many sensors as they are not a closed loop EFI system yet. But with almost all the sleds now with EFI I have not talked to one guy that would go back to carbs nota one and for sledders to agree on something means allot. I know dirt and snow are apples to oranges but both have to take very harsh conditions.