Okay
Is there any difference between a 1.7 computer and a 2.0 computer?
Are they interchangable for either engine?
Does one or the other offer higher performance?

there are VERY specific combinations of ECU, MPS and CHTs that will work together. none offer additional performance but some run better/smoother.
read and learn!!!
http://members.rennlist.com/pbanders/djetparts.htm

AND if you are looking for a 2.0 spacific ECU try to find a 75-6 (052 i believe). it has other features like shuttung down fuel on decel, helping emmisions and fuel economy while not sacrificing performance. i think this may however be on the later 052's from what i've read. when i went from 1.7 d-jt to 2.0 d-jet on my 2056 i found one. from the minimal driving we've done it seems great.

mike

Matched components would be an 052 computer, 049 MPS, 012 CHT. Makes a 2.0L run really nice.

yep. hey slits, do you know anything about the early/late 052. is there anything to that?

mike

ECU is the same for a 73 1.7 and a 73 2.0