You took it to a Chrysler dealer? This is going to go very bad for you.

The car is a Mercedes SLK320 with a different body - I know Mercedes won't look at it (and that pisses me off to no end) - so your best bet is to take it to a local independent shop that is known for Mercedes expertise.

At a Chrysler dealer, you will be paying them to guess, make phone calls to Chrysler (who knows nothing about the car) and grope in the dark.

Another thing, if they really have a Crossfire-compliant STAR system, $85 is justified. If they are charging you $85 to read CEL codes - well, that is a dealer for you.