I don't think that is true ...
Hi there Poorsche,
I am pretty sure all you have to do is buy the new PSE, phone cradle/holster, and phone for your SL. Just those pieces alone are about $1000 though.
I have the SL install instructions with parts lists for the StarTac, Timeport, and V60. The brackets, hardware, harnesses, D2B cable, PTT lever, etc, etc, are all the same. The dealer may tell you it is not compatible, but it is. The PSE is the brains to the entire phone system. The two latest "AutoSense" PSE can tell the difference between each of the three phones. As long as you update that the rest of the hardware is compatible.
Believe me, I know ... the dealer insisted I could not put a V60 in my 2001 ML. They have been instructed to say that. They only offer V60 retrofits to "S" and "CLK" models. The retrofit kits will work in any MY Mercedes with a StarTac or Timeport phone. The hilarious part is even though they said it wouldn't work, the instructions on how to install it into my ML are on the Mercedes TekInfo website!!! Let me know if you want the intructions. I downloaded all MB model and model year phone "install bulletins" from the Mercedes site a few weeks ago!!
Go to my website and download the "MB Technical Telephone Manual V4.5". It gives a lot of good info.
http://home.earthlink.net/~phdwebsite/
Paul[8D]