I had to have a new key made for my '88 sl recently and I was surprised the dealer was cheaper. I went to one key shop and they couldn't do it. Another wanted 30 bucks. I went to the dealer and they only charged 25 (I know, only 25 buck for a friggin' key). You have to give them your VIN and proof of ownership. They don't even take your key to copy. They have a new one machined from their records. It takes about 3 days, but they key is smooth as silk.