I have an '82 528e with the non-socketed ECU. What year did they start using sockets for the chip in the ECU? Obviously i'm looking to install an aftermarket chip to see if i can get a little more performace. I've seen a few mentions of getting an ECU from an '85 535i, but is that the only one? Is '85 the earliest year that had sockets, and are there other models besides the 535i i can use? Do they all have the same connectors?