I don't think the engine generator would be used any different than using the Onan. Is the Sprinter at fast idle louder than the Onan?
With the modern gas, and Diesel engines I really don't think 45 minutes of idling is a problem as far as engine wear is concerned. It does burn gas, and cause pollution, but so does running the generator. I know the Sprinter needs to be driven at higher speeds after idling, or extended urban driving to clean out the DEF filter, but other than that I don't see a problem.
The owners on the Rt FB page, who have the conversion, all seem pretty happy with the performance. I don't know enough about it to form an opinion, so I can't criticize, or applaud it.
