I must learn to read things more thoroughly and not to skim But back to the point, they are wrong. You should not use eec ecu's from a different size engine on your engine because the ecu uses the engine size to calculate LOAD which is used for all manner of things like fuel and spark table look ups. The ecu will be using the wrong results of these look ups if the engine size is different.

If you fit different cams then ideally you would want to chip the ecu to take into account the effects of the cams, this might be going a bit too far expense wise for the gains though. You definitely should try and get a RS1800 ecu, or chipping the 2.0l to tell the ecu of the engine size change is another way of doing it.