The head is aluminum, im sure there is some warpage. The w123's had cast iron heads which made it very difficult for them to warp, and cause damage. The 606 is not as robust of a motor as the 617's or 616's, I would highly doubt that this car is in good condition. There is a reason he is selling it for 2k and if it was a creampuff at 400k miles, I am sure he would have said so. The electrical problems are also something to take into consideration, it is very rare for a w124 to have these kind of electrical problems unless they were invloved in some sort of accident.