As told in my dad's Rover 213 topic, here are some differences I came across because I own both versions.
The Rover 213/216 series was a product that the British brand in cooperation with Honda, so that both companies could benefit from it. Honda would learn something about the European preferences and tastes, and Rover would have a fine basis to work on (they were a bit "tight" on money to make their own). And also, Rover needed something to erase some reliability failures in the past: what could do it best than some Japanese products, in the 80's?
So, Rover took some 3rd gen Honda Civic 4Ds, and made some changes in order to have more appeal for the european market.
The first ones, from 1985 to 1986, were the most similar to the equivalent Civics. Changes consisted on:
Rover seats. They were the same that were used on other Austin-Rover products, at the time.
New front and rear end.
They used a different radiator, with an expansion tank and no radiator cap.
The exhaust sistem was different, with just one silencer in the middle section, and two at the back. It proved to be quieter than the Civic.
The Rover also has a little bit more concern with the soundproofing subject.
Suspension changes were made. I never got to know what have they done exactly, but I think they had their own spring rates. I drove a 1985 Civic, and I could tell it was not as comfortable as my 1985 213, partly because of the seats, and partly because of the suspension. But, I had more fun on the Civic, to be honest. And also, Rover 213s are normally higher than Civics.
The instrument panel is a little bit different, with an 80's square design touch to it. And it has green illumination.
In Portugal, normally we have the higher specification model, the Rover 213SE. As standard, we have 4 electric windows, digital clock, chrome window surroundings, rear defroster, rear armrest, among other things I can't remember right now.
But now, the pre vs post restyle comparison:
Interior:
The first thing you notice, is the lack of the centre console in the pre-restyle (mk1). All mk2s have it as standard. So, the gear stick gaiter is smaller in the mk1.
Mk2:
And the knob is different, too. The mk2 knob touch is better.
mk1:
mk2:
The heater control graphism is different.
Mk1:
mk2: