That's the second post I've read about someone complaining about the noise level adjustment. I've never noticed the volume going too noisy or too quiet. I've got it set to level 14 and when I'm flooring it on the motorway, I can barely hear the engine and the sound has gradually worked it's way up. On the subwoofer side, it feels less involved when you're actually travelling along, but when the car is stationary it's pretty noticeable. I find myself turning down the volume if I'm at the traffic lights in case I come across as a Mr Boombastic type /ubbthreads/images/graemlins/wink.gif Anyway, I love the Bose system and will probably get it again depending on the next car I get.
EDIT: Not sure if it's on the standard speaker spec, but with Bose you have a center speaker up front by the windscreen that really makes the sound come from in front of you. A week after I had mine, I drove my girlfriend's Golf without any special gear and I thought one of her speakers wasn't working until I leaned over to hear if the sound was coming from it. You tend to get spoilt from having a Bose system.