Redpower, We have a 65C with 30" belts and a 65E with 35" belts. Neither have any weight added. If your looking for minimal compaction, I doubt you'll be able to use the extra power of the 75E unless you load it up with weights, which sort of defeats the purpose. In some cases you'll be able to pull a heavy load at higher speed, such as a ripper, but I'll bet your equipment would probably work fine with the 65E and you can stick the extra $ in your pocket. For that matter, a 55 with wide belts would probably do a good job in heavy tillage also. There are several fundamental disadvantages to the large frame Cats: 1) Vibration on hard surfaces at about 10 mph. This usually isn't a big deal since you can just speed up when your on the road and you're usually going slower in the field. I think this is worse on the 35" belts, especially after they are well worn. 2) You will get some berming when you turn in soft soil. Not usually a big deal. 3) The differential steering can eat up quite a bit of HP. I notice this mainly when the tractor is heavily loaded. 4) When you go over teraces, the tractor will kind of toss you forward. 5) If you will have to run through water, like creek crossings, you should consider the slotted driver. The standard driver will loose traction when the belt is wet. In my opinion, none of these would make me consider tires, but I might test drive a quad trackIJ Mechanically I think you'll find the E series fine. Keep at eye on the boggie wheels for leaking seals and replace them if they leak. When conditions are the worst, the wide tracks will really shine. I don't have any experience with the narrower tracks or the row crop units. You'll really like the way soybeans come up in the tractor tracks just like they aren't even there. As for the economics of the tracks, it's tied to the weather just like everything else. You'll be able to get out in the field much quicker when it's wet. Sometimes that can make quite a difference. The cost of compaction is supposed to be tied closely to your soil type. I'm told soils with uniform particle size (clay and sand) don't compact nearly as bad as loam. Who knowsIJ