There seem to be quite a few posts on this board about the ABC suspension system - it seems to be a bit problematic and the fixes are not cheap. I don't think even basic diagnosis is possible without factory computer scanning equipment.

The SBC brake system also requires a computer to put the brake system in 'sleep-mode' for routine brake pad changes. Somebody here did find a way to do it without the factory scan tool but the procedure was complicated.

It's not really possible to answer your question about ownership costs, every car is of course different. But generally speaking I'd guess the average ownership costs of an E500 is going to be higher than a comparable Acura.

In some cases much higher. Cavet emptor.

__________________
98 Dodge-Cummins pickup (137K)
13 GLK250 (157k)
06 E320CDI (341K)
16 C300 (89K)
82 300GD Gelaendewagen (54K)