with sr and ca some parts are interchangable with some us models with sr20de/ca18de fwd motors. i had to order a water pump for my sr20det online and got it in 2 days.

as far as emissions, it all depends on the tune and what emissions control parts are still installed (cats). Ive read of many people around here easily getting sr's to pass emissions with only a cat. im sure ka-t would be the same as long as its got a good tune.