I recently purchased a 1981 528i manual 5 speed. It has about 311k miles on it, but runs just dandy. The gentleman I purchased it from had it in storage for a while(The paint had leaf imprints all over it, among other things). The gas tank recently sprung a rather large leak, and I had to have it replaced. Is it common for this model to have a gas tank rust through at the seams ? My other question is, did they make a 1981 M528i ? Because It had some M parts on it, and I'm wondering if it really is an M, or if it's just for looks. Glancing at the column with the message boards, I would guess that they did in fact, not make an M5 with an E12 body style.