Is it possible to retrofit a 1992 500E with keyless entry or the MB Teleaid system?

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2002 ML320 (thereby making my 560SEL my "spare).
1992 500E, pearl black, 27,000 original miles as of 7/2003.
1990 560 SEL, black pearl metallic, sweetness to drive. Fully outfitted with driving countermeasures (Beltronics radar/laser detector and Uniden BCT-12 Bear Tracker scanner).
1985 Porsche 911 meteor metalic gray, a rocket to drive.
1988 Chevy Silverado pick-up (gotta have something to drive to the rodeo!)
1978 Corvette Indy pace car for show
1971 Opel GT for sentimental reasons