Mooney M20E: pre-1969 vs 1969+

I understand that in 1969, Mooney implemented a number of changes in
the M20C / M20E models. A friend and I might start shopping for one
of these planes in a few months, and I'm trying to figure out what's
important and what isn't.

1. Does the larger rudder in the 1969+ models have a positive impact
on crosswind performance? How about forward slip performance?

2. The top of the green arc was increased from 150 MIAS to 175 MIAS
for 1969+ models. Aside from the rudder, are there any airframe
changes that might explain this change? Is the '69+ plane stronger?

3. Although I've never used it, I like the idea of the "johnson bar"
manual gear system. These are unavailable in 1969+ models, and I'm
slightly concerned about the increased complexity and maintenance
costs that might be associated with the electric system. Is this a
valid concern?

4. Aside from the improved panel layout, are there any other
noteworthy differences between various M20E model years?

Thanks!