Keyless entry?

["Craig D. Niederst" <niederst@telerama.com>]

There has been considerable talk lately on the List lately about keyless
entry. I was wondering if it is possible to retrofit keyless entry in to an
Audi that does not have it? My 100S does not have keyless entry, but the
100CS model does. Looking at my Bentley wiring diagrams, the central
locking/alarm system/interior light delay module are the same between the 2
models. The only real difference I can detect from the wiring diagrams is
that there are four additional wires coming into the module on cars with the
keyless entry (2 wires each from the 2 infrared sensors on the B-pillars).
Am I missing something here? If not, I'm figuring the two needed B-pillar
trim pieces that can accommodate the sensor, the 2 sensors themselves and
the transmitter key are very expensive (unless I could find some used), so
aftermarket would be preferred. Anyone ever try such a retrofit? Any
aftermarket systems out there work (and still arm/disarm the factory alarm)?
Or am I stuck looking for a used system off a wreck? Any advice/comments
appreciated.

Craig
'92 100S (76k)