Sam,
I spoke to Kevin(my brother) and here is the skinny. Starting in 84, the 911 had the better Bosch ignition which is more dependable and has better performance. He thought the 84 had around 217 horsepower(3.2). In 87, the next big improvements include the G50 transmission(better manual), bigger clutch and higher horsepower ~ 221hp. I dont know if that is from the 3.2 or the 3.6. I forgot to ask.
Concerning his rebuild, he had to rebuild his top end because he over rev'd the engine coming home from work and bent an exhaust valve. He said it is not uncommon to do. The rev limit is a spring based type. Concerning his rebuild, I was off base on this, he rebuilt the top end and and replaced exhaust valves/guides etc. Ed Pimm did the machine work. My brother did the rebuild and his cost for the machine work and parts total around 3K for this.
I can tell you his 911 is one beautiful car. I know you dont like verts, but his a vert and he built a roll cage(that he can easily remove), lowered it and polished his wheels. He has his 911 set presently for getting his NASA license, so built a couple of grap hooks on the car too.
Overall, he said that the 84 and newer 911's are great machines. If you have any more questions, let me know and I can hook you up with him.
-Rick