The D6E was made in the early 90's and has a standard diesel engine. The D7E is the diesel-electric machine.

Correct. Kubota does not make anything larger than approx. 150hp, which is kinda low for modern farming. Have to buy a JD, CNH, or AGCO for the larger machines.

Towing 35,000 lbs is fairly easy for most midsize tractors. Spent many summers towing Krone balers (32,000 lbs loaded) with Challenger MT635’s (18,500 lbs). Capable of 35 mph, and would commonly travel 40-50 miles from one field to another.