Any major difference between 84 + 85 300D?

[asnowsquall]

I know where there is a nice 300D with only like 146K on it. It has been family owned, 1st the grandfather, then the aunt for about 10K, now a grandchild. Working on getting more pictures of it. It's gold and they said the lowest is $3,200 which considering the mileage isn't to bad. Has been garaged its whole life, but it is a New England car so I'll have to have a close look to see how the rust is. What I'd like to know is wasn't the 85 like considered the best year and if so why? 84 and 85 should have the better auto tranny right?
Thanks for any input,
Dave