Sorry, Boca, been out of town. Two different perspectives on this. 1) the guys at Mercedesshop quit selling this solution because of the support calls they took made it not worthwhile. 2) It's really a pretty easy install. I think I could do it in less than an hour.
Jim Villers did his E320, I think it was a '94. He used the scotch connectors that the Mercedesshop folks recommend, which is easier than soldering. He and I have both found that the connection to the convenience system as the Mercedesshop folks recommend, isn't necessary for the factory alarm to work.
As for the folks at the window tint and alarm... I've had a dozen similar emails from folks who have encountered EXACTLY the same thing. The Crutchfield solution works fine with the vacuum...
'57 190SL (toy)
'08 S5500 (mine)
'09 CLK550 (wife's)
'06 SLK350 (daughter's)
'11 GLK350 (daughter's)
'03 CLK310 (spare)