Upgrading a 733i with 735i parts

[Crimsonguard6]

I have an '84 733i with tired interior, non-working electrical parts and mismatched wheels. I have the opportunity to get an '85 735i for a good price which has a good interior and electrical parts that I need. Question is, are these interchangeable. I'm looking at the entire interior to include seats. Two differences I saw were the back headrests and the different power window switch locations, both an easy fix ( I think). Is there anything major I'm missing on that? Also, looking at the wheels so my are all the same type (I have 3 chrome 1 aluminum). A/C controller needs to be changed also (bad microswitch). Car supposedly has new rotors and brakes which I'll use also if they fit. Am I going down a bad road with this thought. My 733i isn't a dreamcar but it starts everyday, gets 18+ mpg driving in the city and cruises just fine at 80mph so I don't want to scrap it just yet but a complete restoration is out of the question. Cost of the donor car is under $500.
Thanks