Besides my failing front air springs, failed rear shocks and non-functional head-unit screen, what the L322 really needed was a subwoofer upgrade. Modify before you fix etcetera.
The early L322s with the "BMW-era DSP" systems come stock with 2 cute little 6" subs which simply resort to distorting when asked to play bass. They had to go; unceremoniously dumped in the bin and replaced by the smallest (by smallest, I mean cheapest) 6" subs I could find.
How is that going to fit, she asked.
By bringing the heat in the form of a heat gun which was deployed to create clearance for the magnets within the box. Apply the requisite sound deadening to the box and surrounding areas. While you are in there.
The bottom sub needed a spacer to fit, which meant I had to break out the heat gun once again to reshape the boot trim to create clearance.
Yes, the Targa logos are higgeldy piggeldy, what you gonna do about it?

They are in this orientation because that is the only way the original wiring reaches their terminals and also because I didn't try make them straight and beer was involved, OK? OK. Now, lets forget this ever happened.
Obviously forget to take a boring picture of my empty boot as evidence that it all fit. It wont be easy, but you'll just have to believe me.
Threw in a Digital Designs SSA4.500 amp which uses the 4 original subwoofer wires as high-level inputs to drive the new subs. Now I sound like a gangster when I do slow drive byes in my lobsided Range Rover.

I'm very happy with the outcome, for not a lot of effort/money, I have un-castrated my sound system. Win!
Now to get a proper head unit so I dont have to raid my wifes collection of early 2000s CDs which seem to mostly consist of divorced-dad rock. Yuck.