It's like the S60, VW W12, old V12 Continentals, etc. If it's expensive to maintain no one wants to buy it off you so you get hit with massive depreciation costs. You can get a 20y/o 'no issues' 500+hp V12 Continental for 10k where I'm at. They've had a brutal cost/year and cost/mile.
I've driven a 2003 Volvo S60 (plain 5 cylinder, no turbo), which matches your 20 years - and most diy repairs were quite straightforward. I suppose you're talking about some Mercedes or other brand I'm less familiar with?
