Someones garage or driveway .... but I don't think that they would appreciate you snooping around their car ...
I have been to many scrap yards , and in the past year or two , I have never come across an M3 E46 , Either they are not being scrapped, rebuilt or repaired, or the current owners are looking after them. But , I have a feeling that you should check with Mandoes , the one near mobeni opposite the corobrick yard.
They could have one , All the M3s I have ever seen were in that yard, they tend to buy very high end cars to strip. Saw a CL500 two door and an S55 AMG there a few months ago .