i myself am an alignment tech.....and i work for goodyear in an extremely upscale neighborhood, so bmw's, benz and lexus' are the norm......the only mercedes we turn away are all ML's because of their rear caster.....the dealer is the only place that can measure and adjust rear caster....and if the alignment is done without measureing and adjusting rear caster, then the warranty becomes void...... ....most mercs have rear camber/toe adjustments, aswell as essentric lower conrtol arm bolts for front camber/caster.......i know alot of shop turn them away for the simple fact that they dont want the hassle, because if the car is way out of whack, then it can easily turn into a 2hr alignment.... i must admit that i dont use the presser bar or the rear ride height tools, but because i use the latest hunter machine and i've also been hunter trained, i do'em with extreme confidence....although i am aware that using the presser bar and that ride height would give me a much more accurate alignment....im actually looking into buying those 2 tools, as soon as i find'em.....