To public enemy: there's two things I pay for; parts and tuition.
To the subject at hand: I've had four Peugeots, their suspensions excell Mercedes and comparing the two are tuned to being imune to the arc of the road. My 190 seems to be pretty sensative to that. Relitive to the Peugeot there is a big difference in that, but its all in the name of awareness that I'm all for. Most cars try and hide the fact that you're even on a road. Most of my driving is on divided highways in the fast lane so most of the time I'm driving on a left leaning surface so I asked them to set it for straight and level. I don't know about dealers but some shops if you make specific specifications, will follow them, but you have to be right, like if you're going to race in an oval they will set it up for you, but you HAVE to be sure they know which way. As far as your ML still pulling, you could ship your car to a left hand drive country, like England, and try it there, or file a flight plan with the FAA and try it on a level runway, I'll bet they're straight and level.