I installed the 4771 in my 1993 325is (E36). Works great.

The most time consuming parts of the install were

1.) Accessing the car's existing
reverse wire. It's blue with a yellow stripe, identical to the wire in the
Becker BMW adapter harness. I attached to it as it passes through the large
wire bundle located under the foot rest on the far left side of the driver's
footwell. Although I could see the wire at several locations, the trick is
finding a location you can access with your trusty soldering iron. By the
way, I confirmed this was the correct wire with a multimeter before I tied
to it. That step is probably unnecessary since it is the only blue wire
with a yellow stripe; and

2.) Routing the reverse wire from
the Becker BMW adapter harness over to that footwell location. The install
would have gone much faster had I simply grounded the reverse wire on the
harness. However, I'm too obsessive/compulsive for that.

The GAL wire hookup was no problem at all. My car had the GAL wire (black
with white stripe) wired to the pin 10 location of the existing radio
harness, so I didn't need to search for it. So I just bought the pin and
wire from BMW (part number 61 13 0 007 452) to fill in the pin 10 location
on the Becker adapter harness, and soldered the new wire to the loose
black/white stripe wire from the Becker harness, and I was set.

By the way, my car has a November 1992 build-date, so I believe any of the
3-series E36 cars (1992 thru 1998) should have the same color wires in the
same location. I checked the electrical diagrams in my Bentley E36 service
manual, and it appears all of the 3-series used the same wire color-coding.
GAL is black with white stripe, and the reverse wire is blue with a yellow
stripe.

Tony, when I purchased the adapter harness from you mentioned you were
uncertain whether it worked with an E36 as old as the 1993 model. Well, it
works like a charm.

Devon