You know I have a feeling the e9xm3 are going to be strong on the resale end when productions stops. I saw it with the e46m3 as well as we waited for the e9xm to come out. A lot of it will come down to A. The release date of the new M3/M4 and also how much the new M's will be.
Will the car go up in value no, but it will hold strong value I feel once productions ends.