We have a 5410, mfwd, cab, and loader with about 2,000 hours that we bought new in 1998. I was considering trading for a new 5100M or 6105M, until I found out about all the engine modifications to meet the new emission standards. I particularly don't like the regeneration. How far back would I have to go to buy a used tractor without regeneration? And, yes I do realize that there is quite a bit of difference in a 5100M and 6105M, including about $14K in purchase price when new.