The fellow you visited was right about the Hunter alignment system. It costs a fortune. Properly used, it is the OEM service system of choice for both BMW and Mercedes Dealers. However as with all sophisticated suspension measurement systems, it requires the technician to meticulously follow the set up for each vehicle whch will differ widely by manufacturer and model.He (or she ) must be properly trained and familiar with both the system and the vehicle to which alighment is necessary.
Both Merc and Bmw spec. custom filled water bottle weights by model to be inserted into the passanger footwells to arrive at an average vehicle loading before any settings are adjusted.It should take about two hours to set up a car properly if adjustments are required as changing one setting will mean changing many others.
The idea of driving into a multi chain tyre garage and being told your wheels are out of alignment and it will take 2 seconds and cost twenty quid is a false economy given the costs of fuel and tyres that a four wheel alignment will save over a couple of years. Noise and vibration over 85mph will also be considerably reduced for those of you driving in Germany because it is at these higher speeds that Mercs were originally designed for where four wheel alignment is critical. The good news is that whilst a main dealer will try to charge £285 or so , a private with the Hunter equipment and automatic access to manufacturer software set up discs will charge about £125 or so.Try a Merc approved Body shop perhaps.
Blueanybear