My local dealer charges me only $90 for a full 4-wheel alignment. If it's not right, I get to take it back for FREE.
Also, get it aligned with the stock wheels & tires if possible (assuming your wheels are true, and your tires aren't badly or unevenly worn).
Make sure they get their BEST person to do your alighnment- remember it's not the equipment, but the operator. An excellent tech with string and chalk will do better than most who just "set the toe and go".
Also, make sure they give you a printout of the specs before and after. Also, if there are SportLine alignment specs for your chassis, get those, since you lowered and stiffened your suspension and are going to extrememly low-profile tires. They should also use the proper spreader-bar for proper toe set.
I've tried two alignment shops who have received glowing testimonals, but when it comes to Mercedes, they just don't do enough and have the experience.
My dealer does THE BEST PERIOD.
1988 360TE AMG