"COVID-19 Stay-at-Home Project," or how I modernized the audio system in my '87 911 Carrera Coupe with no cutting or modification, and keeping it looking period correct. The key component is the relatively new Blaupunkt Bremen SQR 46 DAB head unit (unfortunately only available from retailers across The Pond). It replicates the original, first produced in 1986, however lifting the mock cassette door reveals inputs for USB, SD card and phono plug. There is also a rear USB and mic input, along with excellent Bluetooth connection with smartphones and other enabled devices.

The original Blaupunkt Reno is below, new Bremen is above.

The old wiring harness from the Alpine CD player that inhabited that spot for the last 27 years.

The new harness with soldered/shrink tubing wire splices, wrapped in cloth tape.
Next up, a subwoofer is a must, but where to put one was always a bit of a conundrum. Awhile back I found an excellent compact unit, the Kenwood KSC-SW11 and located the perfect spot under the passenger seat, it even has 3, pre-existing, treaded potential mounting points.

A 9x13" piece of 1/4" plywood was used with appropriate holes drilled.

Fits perfectly.

Because the new Bremen is not as deep as previous units, all wiring tucks neatly behind it.

Location of the microphone bug.

The final setup, display color and brightness custom tuned, phone Bluetooth linked and connected to the rear USB (data and charging) that was routed behind the dash and audio settings adjusted.
The sound is amazing, even with my many years old Polk Audio coaxial speakers. The bass is exceptional for the small package due to the solid mounting to the floorpan. And there you have it, a modern system with an '80s look.