The only easily detectable difference betwen the various lenses that you may buy is between the multi coated and the single coated. The single coated is nicer with mono or color, but may flare more in extreme sceanes.
Originally Posted by osprey48
The 5cm Elmar from 58 on is a bit soft in corners, the earlier 3.5 is better, but you might not detect this difference, the modern post '94 Elmar is modern, and performs well.
You may be more annoyed by the handling differences of the lenses, finger size and length dependent... I have to slug any of mine with heavier lube to stiffen the rings
There are other LTM or M lens suppliers e.g. Konica