The engine wiring harness only affected M104 engines from 93-95, so that shouldn't be a problem.
I really haven't heard or read of evaporator problems on the 400E W124's like we've all read on the W140's.
I think other than the timing chain / guide replacement every 100,000 miles, I can't think of anything specific to this model that doesn't affect other Mercedes models.
2001 E430, Bourdeaux Red, Oyster interior.
1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".