Yeeeeeah...I'm not so sure about a W124 E420 anymore...that thing is
expensive to maintain if/when something goes wrong.
A typical fault is some wiring harness in the engine bay, which due to the extreme heat of the V8, tends to melt. Over 1000? for a sparepart.
Lower ball joints need changing ? Nope, you have to change
the entire lower suspension arm with it, because the damn thing is one solid piece...around 400?/piece. Problems with the throttle body/-valve ? Beyond 1000?.
The M119 V8 is one expensive piece of engineering to fix. X300 Jag is a bargain compared to that