I was just surfing JD site and see they have a new 4 series compact tractor They have the "4x20" series tractors as well. New one's look nice but they have a Yanmar engine. Also, you can't go to their "build your own" for the older series tractors - only the new ones. So I got to looking around on JD's site and I don't see any Tier 4 4024 engines anywhere - industrial, marine, generators. I notice the new 4000 series tractor's have tier 4 Yanmars (big honking DPF on top of engine). I'm thinking the older tractors are being phased out and JD is not going to make the 4024 anymore (the EPA has killed another engine). I really like my 4320 and wouldn't think of any other compact tractor. But if you can't get a JD engine, why bother. I see they do have a 2.9l tier 4 engine in the industrial line. Maybe it'll find its way into the tractors later? Anyone with more info?