Concerning the 600 HO engine, it is bullet-proof, also, this is a capable snowmobile as it will run in the snow. The 06 600 HO engine is carbed, the 010 engine is fuel injected (CFI). I had close to 4K miles on my 06 600 and it never missed a beat. I replaced the reed valves with V-Force reeds at about 2000 miles, this being the only engine work. Moving up to the modern chassis is a good thing, the $3000 price may be steep. Just be aware of the cooling issues. At the time, my 06 IQ Switchback (converted to an RMK) was the best snowmobile I ever owned - then came modernization. It is hard to look back. Sorry to sound negative but the ice build-up in the tunnel diminished the experiance. Cheers.