OK, that's clear. Thanks for your input, the unanimity of your responses really clarified my (what passes for) thinking.
The Green One's a keeper. I'll get it running and decide if it needs more power. I guess I'll have to join the lepers in the 4-door thread, too.
I'll drive the red one until the Green One is ready, then depending on the power question I'll sell it whole or as a rolling chassis.
Now, who wants to play L-Jetronic?
Anybody got a set of trailing arms with disc brakes attached?
Proud owner of a Green, Four Door E30