Interesting change Jack.
My uncle recently got his ML320 CDi and he's really enjoyed it. I have yet to have a ride in it, but my uncle also owns a W211 E500 4Matic. He says the difference between the two vehicles and how they operate really is night and day.
The E500 feels like a sports car in comparison to the low revving ML. One question, why did you go with the GL, rather than the ML? More space, exterior styling?
