The 507 and 509 have a more refined sound over the 505 that is going to be noticeable on your Be. I think the treble refinement and warmer character of the 509 is your ideal. Still, you have 328s and they really should be fed some massive power. The Luxman will get it done, but not quite what they really want for power. Someone mentioned Anthem STR integrated. If you can manage separates, the STR power amp is really where you want to be looking, power wise.
Integrated amps, unless they have BIG power, are going to let you down on 328. Strap big power to them and you'll get superb bass!

