I'm sorry the Safety issue didn't work with your wife. Mine hasn't had the intelligence to factor in speed yet to the equation.
Please don't let your wife talk to my wife.lol
Good luck on the 400E. Fwiw, If it were me, I'd narrow my search to any 93-95 W124. You get all the interior changes that were made to the W124 in its final 3 years. You get the M104 engine 6 cylinder engine or the V8. You get the dual airbags. Further, the only real significant flaw is the engine wiring harness issue in the M104's. If you buy a 6 cylinder, check to see if its been replaced. If not, budget $515.00 for the harness, and 2.5-3.0 hours labor to install.
I know the 6 cylinders leak oil at the head gasket, but the leaks seem to occur between 100,000 - 130,000 miles, and that's not too bad in my book. Besides, gaskets weren't made to last forever.
2001 E430, Bourdeaux Red, Oyster interior.
1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".