More Power or use subwoofer to boost bass for music

My thoughts: 1. The speakers can sound "punchier" at the dealer because they usually crank-them-up. Since a typical Magnolia room is larger than a normal home room, they can play a lot louder without overloading the room. Being placed close to the wall enhances the bass. 2. Are the foam plugs in the ports? This reduces bass quantity. 3. I'm a proud 804D3 owner and, yes, these speakers need reinforcement.

One thing that usually isn’t taken into account is the fact that, regardless of power, placement or how great we think our hearing is, human hearing is Not equally sensitive to all frequencies at lower to moderate volumes. So if you are speaking of low bass down near 30Hz, you would have to be listening at a nominal volume of about 80db before the bass seemed adequately loud and for frequencies approaching 20Hz, the listening volume would have to be up near 100db (considerably louder than I care to listen, any more). On the high end, frequencies perceptively balance out at about 60db. Thus was the purpose of the old loud button on many of the vintage amps.
One advantage to a good, well integrated sub/subs, is the ability to boost the bass volume to accommodate listening at moderate volume levels, without loosing the bottom end bass. It could be that you were listening to the music, at the dealer, at a louder level than it seemed. Not to take away from the other suggestions, but just another case for a good, well integrated sub/subs...Jim

That's Fletcher Munson equal loudness curves you're talking about. Duke has said pretty much the same thing. One consequence of this is its important when setting sub levels to do it at a level you care most about. 

I use matched amps and pre-amps for my older 803's and subs. This gives me control of the bass without creating out of phase signals. It also allows me to tailor the bass for the recording.  Many old albums really open up when the bass is not relegated to a recording mixed for what a 1960's 35 wpc amp could produce, or a modern AVR receiver.  Powered subs with frequency roll off controls, as well as tone controls, alter the phasing, thus negating B&W's primary design philosophy.  They are also hard to adjust for each recording. 

Also, you might want to use your amp for the subs, then get a less powerful amp for the 804's, if price is a consideration.  100 watts will easily power them, as long as you are using subs.