Here's a thought on X350 alignment. When you start the car it rises slightly and according to the manual, the car lowers the ride height at highway speed. So we have three different suspension geometries: ignition off, engine running, and engine running at highway speeds. Since there's no easy way to activate highway speeds suspension setting when doing an alignment. Should the alignment be performed with the engine running or not?

 

That is very interesting, I had never thought of that!

I would think that if the engine has been recently turned on, the car will be at the appropriate standard height. Keep in mind that the X350 only lowers itself at speeds above 100 mph, and only by 1cm or so. Also, the car does maintain ride height when a door or trunk is opened.

 

I measured the ride height this weekend 10 minutes after I had shut off the engine then right after restart and didn't notice any difference. I'm guessing there's no real difference. If I get the time, I'll grab a calibrated bar for a good reference surface and gigantic calipers from the shop and get a more reliable measurement. For now, it seems running the engine or not doesn't make a difference when performing an alignment.

 

IT WOULD BE MORE IMPORTANT TO CHECK STACKED TOLLERANCES IN THE FRONT SUSPENSION WHEN SETTING FRONT TOE(AKA MERCEDES ALIGNMENT)
AND THEN IF YOU REALLY WANT TO GET PICKY THEN THE WEIGHT IN THE CAR AS NORMALLY DRIVEN ieee. DRIVERS WEIGHT IN THE DRIVER SEAT