Just look at any car with a salvage title, I can spot body work a mile away. Not have panals fit would drive me nuts on a $70k+ car.
Maybe its just me but I would pay extra for a one owner example with 0 accidents. Their is something to be said for nice original paint and sheet metal.
Local shop has the MB diagnostic tool, I think they charged my friend $70 or so to diagnose his car.
If you don't want to buy a $15k S320 and pay to fix it, you could probably find a leftover 2006 S350 kicking around. Pay $70k and you will have a nice warranty and not have to pay for repairs.
After 4 years or 50k miles buy another new one.
Or buy a BMW, they cover everything but tires, no out of pocket expense. Well excpet that payment...
I'd rather just cough upa few bucks to fix the W140 once in awhile.