at this mileage you might be looking at timing chain guides and check if there is delay when putting the transmission in reverse because I don't expect the tranny to be fresh after 182k and behind a V8.

400E have a throttle by wire and can go into limp mode because the wires inside the throttle body can go bad and also I think there is a bottom engine harness which can go bad

A/C evaporator fails are not exactly uncommon on W124s. Dash out time.

These cars have a 2.24 axle ratio so low rpm at speed

I think $2k is a fair price for it