ok.... firstly, please DO NOT confuse the SP20 with the "Sport20"... they are completely different cars. "SP20" is not a shortform for "Sport20". They are exclusive to each other. SP20 is Aussie only and those cars have the same FS-DE as you blokes do in the UK. The Sport20 is the one with the FS-ZE and have many subtle trim/equipment differences. Please use the correct terms to avoid confusion because some people will think you're referring to the Aussie SP20. If anything, you can consider your cars "SP20s" as they are essentially the same as the Aussie ones, save for brakes and interior differences. Furthermore, the Sport20 was available both in PFL and FL. The SP20 was FL only.
As for the swap... here is what I know:
You can easily swap the engine into the car and use the FS-ZE ECU as long as you swapped the engine wire loom with the one off the 1.8. The wiring scheme is nearly the same and just takes a few modifications to make it work. It's a near match!
All FWD Sport20s are automatic
4WD Sport20s were available in manual and automatic... the 4WD system robs a lot of power, and the car probably isn't much quicker than your UK 2.0 Sport.
You can use the 4WD Sport20 manual ECU with a FWD gearbox. That is how Mazda did it with their limited run MazdaSpeed Familia back in 2001. It had a specially modified FS-ZE that pumped out 5 more horses, had a FWD manual transmission that's exactly the same as the UK 2.0 Sport, and used the 4WD Sport20 manual ECU. One bloke in Australia got lucky and found a Mazdaspeed FS-ZE and swapped it into his FL 1.8 not long ago. Dyno results with the FS-ZE ECU was pretty impressive. He recently buggered up his 1.8 gearbox (he reused it because he ran out of money) so he is in the process of swapping in the much better 2.0l gearbox, but he's running over budget as he never realised how many parts he has to change to make it all work!
Best to get the 4WD engines with the manual ECU. The FWD Sport20 engine has a different crankshaft girdle/"upper oil pan block" (as mazda calls it) because it's designed to be used with the automatic gearbox. It has one less mounting hole for the starter. That is the only difference but really doesn't matter though.
Some FS-ZEs come from the JDM 626... called the Capella, some others comes from the JDM Premacy. The difference between the Capella and Sport20/Premacy FS-ZEs are easy to spot. Instead of the plastic "black box" over the top of the Sport20's/Premacy's inlet manifold, it is a cast aluminium piece on the Capella FS-ZE. What's the true difference? I don't know. Engine internals all the same and it's fine either way. Capella ECU is different though, as is the Premacy ECU. Like the Sport20, the Premacy FWD FS-ZE is limited to automatic, the 4WD Premacy was automatic only too.
Only the Sport20s built after August 2002 have OBD2 diagnosis, but still more limited than the UK/Europe or US ones. The older Sport20s don't have OBD2, but the datastream signal lines are there in the ECU for you to tap into to get limited OBD2 codes (only a dozen) and engine data monitoring. ECU wiring is similar between the older and newer Sport20s in any case, therefore, you cannot plug a newer FS-ZE into your UK loom. Just won't work.
