You could try it out by just disconnecting the air pipe from the stock air box and then starting the car with the air feed pipe open, rev up a few times and you'll get the idea of how it is going to sound
Just make sure there is nothing that the pipe is going to 'suck' in before you do it obviously! I did this last night and it sounded really good, adding the K&N filter made no sound difference so its just the same