Hi Jürgen, welcome here!
Above all, you should buy the one in the best condition! Usually there is quite some rust on most examples (also see our
Buying Guide & FAQ section) so before you know it you are looking at a restore.
From the chrome mirror pre facelift versions (prior to Sep 79) there aren't too many left so if the difference in interior and exterior design doesn't bother you, the early one is the most rare.
The Edition S (see here for details:
http://www.bmwe21.net/?page_id=137) was only available in 1982. The 1980 car may have similar specs as all the options apart from two tone paint were already available back then, but it can't be an Edition S.
The dogleg sports gearbox was available back then. However, a 5-speed was not available in 1978. But does that really matter? I reckon at least 80% of all 323i's had a 5 speed fitted at a later stage, and even though I love originality, that would not be enough reason for me to stick to a 4 speed. So gearboxes, not a real issue, just enjoy the fact both have 5 speeds already.
Curious what your choice will be in the end, will you keep us posted? Would be great to see what its going to be! If you need more advice, just ask here!
but I think I will choose the 78.
