I dont really get the OP's post. But in a this over that and why type question, Personally, I like to shoot 50, I like to shoot "boulevard" photography. (aka street) and I just dig the 50, and the 40mm... and there is no better camera for the 50 than the m3. Also, I can tell you from experience, the m3 is more fun to hold, I can just sit on my couch and hold an m3, marvel at how beautiful and heavy and brass and mechanical it is, m6 not so much. While I love my m6 TTL and its mint, I dont marvel at it the way i do M3/M2's .... not even m4's have "it"
Anyway, thats why i would pick the M3... double stroke. 900,xxx serial is best. IMHO. SS is good too though. And if your a 35 guy, get the M2, still better than the M6 to me.
Just my opinions. Nothing more, nothing less.