Ben,
I think some people have misunderstood your issue and assumed that you have the adhesive pinstripes that most cars have today that peels off with a little effort or heat as described above; however, speaking from experience (I also have a monochromatic 300E, all black with smoked hella taillights and clear corners) I believe that your 300E probably has factory painted on pinstripes. What I did will probably make most people here wince and it's not really the best solution but it worked for me (at least for now). I bought some black pinstriping tape from Trak Auto in the two different widths that mine were painted on (on mine the wide stripe was red, the thin stripe white) and basically covered them up. It's unnoticeable from 15 feet but someone looking for it will find it. Regardless, I think it's an improvement in the overall look of the car, since everything is a shade of black, grey, or chrome.
here's a collage of the car taken back before the winter hit:
http://stormworks.max3d.com/collage_1low.jpg
before I get flamed, I know, I know, just because I have AMG wheels doesn't mean I deserve a decklid badge, but hey it looks damn cool. I know I'll have my head handed to me one of these days by a C36 or C43 (I'll just pull over and stop at the mere sight of an E55), but until then I'll just floor it and make people think my car is something other than a plain ol' 1990 300E
that's my two cents (or 10 cents as it turned out)
Chris
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Chris Singh
1983 300D 200k+ (stopped odometer)
1990 300E 123k
1999 E430 12k
http://benz.mp3car.com
http://stormworks.max3d.com