I took far too long to actually start this project, but at least it went fairly quickly once I'd started. Not without a few problems along the way of course. Difficulties with some pins/connectors, having to redo 1/3 of the required pins on the empeg wiring loom/harness and then at the end finding a mistake in the original wiring diagrams I referenced for my custom connectors...

Installed components:
Source: empeg MK2a (Rio Car)
Amp: JL Audio 500/5 (500W 5 Channel, 2x100 front, 2x25 rear, 1x250 sub)
Front: JL Audio XR525-CSi (5.25" components and 1" tweeters)
Rear: JL Audio TR400-CXi (4" coaxials with 1/2" tweeters)
Sub: JL Audio 10w6 in .65cf sealed enclosure (10" subwoofer)

This replaces the factory's amplified 10 speaker system (1 in each front kick panel, 2 in each door and a woofer and tweeter for each side in the back). The sound from the 7 new speakers leaves no comparison to the factory components. It's like night and day.

Speakers are all installed in factoory locations. Front mids in kick-panels, front tweets in the door's mid location (left factory tweets in door but unused), rear coaxials inside factory speaker baskets and left rear tweets in there as well but unused. Sub mounted in the trunk under amp.

Here's an image of the empeg sitting in the single DIN slot in the dash. The stock BMW radio/cassette had to go. The empeg is the only source of music in the car.



And a close-up:



Still need to put a red lens in - and perhapps clean this one in the meantime.