Near as I can tell, the Bowers & Wilkins systems in BMW and Volvo are pretty comparable, so I'm not sure what the basis is for the "X7 can't compete in that category" comment. There's a PDF info sheet on the X7's B&W system available to
download here, and
here's the only info I could find on Volvo's version.
They seem similar, but the X7 uses a 20-channel 1475W amp vs the 12-channel 1400W amp in the Volvo. The X7 also has one more speaker than the Volvo — 20 rather than 19.
If there's any practical difference between the two, I'm sure it's negligible.