I'm gonna buy a new tractor in the spring, thats why i joined this forum to learn all i can. from what i've learned so far i'm concerned about this tier 4 stuff, I went by a Mahindra/ NewHolland dealer the other day and the guy there spent some time on the subject. here's what he said he opened a N/H hood to show me a can/tank. he said that this system you gotta run the engine at high rpm's all the time. if you dont you'l have more regen cycles the more regen cycles means the porcelen core will were out stop up, to replace is 3,500. high rpm's means poor fuel economy and more ware and tare on the engine. also he said not to park them in a hay field or a barn cause thay will catch on fire. then we moved over to the Mahindra he said they don't use that system or the fluid system, they use a really high preassure ingector pump that super atomizes the fuel for cleaner burning. so you don't have to deal with or mess with anything. just use it like the old tractors. not 2 days later i whent by an old frend who has a large farm, to get some input from him. he has/had a really big 100+ case cab, he said it burned to ground in his hay field. i told him what i learned at the dealer and he said it did have that can on the engine, i call it a can cause i don't know the right term. he said someone he know's had his barn and tractor burn to ground. go figure.