I dealt with them about a year ago on an exchange factory radio for my wife's C280, since Fastlane didn't show one. I found a night and day difference between two people I spoke with, one very helpful and one quite rude. It took 3 times to get a good working unit, another couple of calls to get the right security code (the ones on both last last two radios didn't work) and in the end I had to call twice to get the core charge credited. Not a good experience but I learned to ask for the pleasant person and all in all it worked out ok. The extra $30 in shipping charges (for the defective units) bothered me but not as much as my wife complaining of no tunes in her car during the seemingly endless ordeal lol.

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1983 380SL
1995 C280
1995 S500 coupe
1990 Mazda Miata
2004 Suzuki Hayabusa