G, as far as the JDM Imprezas go, the picture in the New Hyper Rev with the up-pipe cat and O2 sensor was of a JDM car, and I recall SCC stating that all
WRXs world wide will have three cats. So as far as sensors monitoring the cats, it seems everyone will have a bit of working out to do.
I also recall Brett Middelton from MRT stating that the new Imprezas are a bugger for fitting aftermarket exhausts due to O2 sensors and their placement on the new cars.
At least we will have the whole world working on a solution( if there is indeed a problem, as I mentioned before)