I am glad I came across this thread, you have reminded me to pick up a filter & some oil for my VW Diesel 250,000 mile oil change. I like Diesel and would certainly prefer it for my TM. I do wish there were more to choose from, as far as I know there are only three (HM, Blueline,
Prochem), they all use the B&S (Hyundai?) engine, which I have heard is not that great.
I have not been able to get any kind of service from the local B&S dealer. I just recently changed out an engine with less than 300hrs on it. Most small engine shops won't touch a truckmount, at least around here. So I am my own warranty station anyway.
There is a difference in the BTU output of the Diesel engines, which would have to be addressed with larger exchangers. I believe that Judson has built a Diesel Reactor which seems to be the best way to get the heat out of a Diesel - liquid-liquid exchange.