heja sverige!
the helmholtz resonator is not removed when PSE is installed on the car, thus you can still hear the intake sound when PSE is on/off. although some people on this forum, mainly some moderator, claims that is not the case
i would recommend you to book a test drive and try for yourself. it is pretty hard to describe the sound with words. if you hesitate between ordering PSE or not, i strongly recommend you to get PSE. from my point of view, it adds so much to the driving experience i could not be without it.