My mom has HK in her S60, I have B&W in mine. Mom got her car first, and I was really impressed with the HK. It has excellent sound staging, and regardless of volume the sound is not distorted and it is well balanced. The bass is full and balanced, but it doesn't quite have the design to make the music "thump" (if that's your thing, like it is mine). HK is way better than many systems, and it is high quality for sure.
But.......B&W is completely on a different level. Yes, at low volume the difference it noticeable. A lot noticeable. The real key here is the clarity and sound staging. The music is true to life, you can hear every instrument in every location, and event he smallest nuance of sound can be heard. Of course, tire and wind noise can hide some of that at speed, so sometimes the full appreciation is best experienced at a stoplight or just sitting in your garage. You really need high-quality audio sources to make the most of it, so if you plan on just listening to FM or SXM you won't experience the true difference between HK and B&W, the difference then is much harder to appreciate.
The B&W bass notes are tight...I mean tight, crisp and completely undistorted. The front woofers in the door just pound, and the rear sub fills the cabin with low frequencies in a way the HK can not. At high volumes the entire door panels can literally be seen moving, the armrest door pulls literally will move back and forth. The right song can make the seats shake, enough to wake my iPhone from sleep and turn the screen on if I set it on the seat. You feel the music as much as listen to it with the B&W.
$3,200 is actually a bargain when you consider what you are getting, but that's not to say it's cheap. Its a LOT of money for a car upgrade, and only you can decide if it is worth it. Your listening preferences and how much of an "audiophile" you really are is something only you can decide. The biggest thing I would say is....if you get HK, will you get in the car and every time not see those aluminum speaker grills and feel "man, I should have got the B&W"? Nothing ruins the enjoyment of a new car more than getting in and every time wishing it had been ordered with a different color or configuration....it's never REALLY the car you wanted. Some people are like that, others are not.
Sometimes you can't miss something you never had, and HK is a great system. But don't be misled by some of the comments that say "oh, the two systems are not really that much different". Those people don't really fully appreciated music or are indifferent to exploring that last 20% of faithfully reproducing the music as the artist intended you to hear it. My cousin is a true audiophile (his iPhone has been sent off and the hardware changed so the quality of the connection to his $15,000 headphones is improved). He recently visited and was eager to wanted to hear the system. I queued some high bit rate dance music and some symphony tracks.....he literally looked at me with his mouth hanging open. His comment was, "This is factory!?!?".
When people that upgrade their iPhones, buy $15,000 headphones and spend more money for their home audio than the entire cost of a car are left astonished by the sound I think it's safe to say the system is "worth the money". For me, one of the most enable parts of the day is getting in the car and seeing that B&W logo looking at me across the leather dash with the nautilus speaker pointing at me, knowing that another sound experience is about to be go down.... It's often the best part of the day. Some people would laugh at that, but if you "get" music, get the B&W.
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