Ecu
 

What is the difference between a N332 and a N333 ecu?

essentially,nothing.
Both are for S4 TII Turbo.
the Ecu likes to see HI impedance injectors.

Whichever ecu u use, the matching harness must go with it.

Not really.You can put a TII ecu in an N/A Harnessed car when you swap from N/A to TII without using a TII Engine harness.Personally been done.
If you use the correct series of course.
S4 to S5 conversion gets a little more involved.

N332 is from an '87 TII & N333 is from an '88 TII. Functionally interchangeable.

https://www.rx7club.com/2nd-gen-arch...ations-873382/

So i can take my '87 turbo ii engine and drop it in a '88 N/A convertible and still use the original harness that's in the N/A to hook up my tii ecu?

Yes you can..BUT you will have to extend some wires on certain sensors.
This is all in threads easily found.
For example..plain view:Look at RotaryRocket88's signature and hit the link.