From a scan of recent posts and listening to a few youtube videos it seems that fitting a Milltek Y Pipe improves and increases the sound of the GTR, which i think is needed! I know that it may well invalidate the warranty (but is unlikely to actually cause any damage as it doesnt add any horsepower). But this is an acceptable risk in my view. My concern is if it significantly increase noise levels when you are cruising along the motorway at say 85 and just want to listen to the sound system or make telephone calls. Can anyone advise? Is the noise a bit worse, much worse? Hardly noticeable, unbearable?