Originally Posted by Bayerische
Sills are going to be an issue on most cars now as they are a weak point.
The plastic sill covers need to come off the car for any E34 M5 to be inspected properly. I have seen cars that look great but when the sill covers were removed there was corrosion.
I have been watching the market closely and 3.6's are now getting very hard to find. The red car above has been for sale for quite a while, perhaps there is room to haggle on the price due to length of time on the market and the rot on the sills.
I think you are going to have sill issues on most cars that come to market, if the rest of the car is good and the price is right, do the work on the the sills and then you know it is sorted.