Thanks for the comments, but it's someone else's now.
Still miss the e34 M5s (and it's the only M5 I'd buy) but wouldn't want to have to spend that much on a daily driver - especially as every time something breaks (not frequently) you can be off the road for 4 weeks while a part arrives. Keeping up the regular maintenance at 6000 mile intervals, and the 12,000 mile clearance checks, for on a 2k/month daily driver was ruinous - although it was all forgotten the moment you drove it on the road or track.
Insurance was only £600/year, but it was averaging less than 400 miles between 80l/£100 fills of it's 90l tank. I even managed a £150 fill up about 5 years ago in Germany. Probably cost £500 a month in petrol. Total running costs were probably about £1/mile as there was always another expensive/rare part to fix - alternator was £600, self-levelling rear suspension was £700/corner about every 3 years, rear tyres 3 times a year, brake discs once a year, servicing 3-4 times a year. Plus you had the general wear & tear on items that hadn't been replaced for 15-20 years and covered 160k miles.
I could have just run them into the ground, but as it was always my only car I needed it in top condition to ensure I could make the 200+ mile journeys to work & back, and also to ensure they were safe for track days & European jaunts (for which it is far better suited than the Z4MC).
I'd definitely have another (preferably one that's already been fully restored), but I'd have to have won the lottery.