[snip]
So, here is my question, if I can land this car cheap, I'd plan on installing a manual box, what are the options here? I'd like a 5-speed as opposed to a 4, what will fit? Obviously, a stock 4-speed, but will a 5-speed fit from a e28?

Also, do any of you know the towing capacity of this car, say, theoretically, equipped with a 5-speed and heavy duty clutch and some HD shocks?

TIA
Matt

Either the 4-speed or 5-speed from big six engines will fit. The simplest would be to get the transmission and matching drive shaft from another e12 car.

As far as capacity, I saw a 528 used as a tow car for formula vee (on a trailer of course).