its strictly not true that the ecu cancels them out.. as we have found out recently.. newhoo..
ive had the jwt dual, nismo dual and now im running the stillen gen 3's... to be completely honest like u said. its a short ram type induction kit so it will be sucking in hot air to a certain degree. the jwt's are by in far louder than the nismos and even the stillens i have on. its a decent kit tbh. manufactured well and if u were to get a remap then u would reep full benefits of an induction kit. it will sharpen throttle response for definate tho.
just get it bought
-ho
ps: it also made the most difference to exhaust note aswell