<font color='#000000'>Brent,
A few hints for speaker auditioning and subwoofer integration:
1) Yes I recommended you take a Radio Shack SPL meter ($29-$49) analog or digital version (I prefer the analog's swinging needle for reading SPL numbers) with you as well as some favorite music you know very well (listened to it a lot and know all the twists and turns) when auditioning speakers.
2) You use the SPL meter and your favorite music to ensure you are listening at the same volume level to each speaker you compare. If one speaker is 1dB louder than another it will typically sound better to your ears. I'd set the meter to the 80dB range, "C" weighting, and slow response. Then you can listen to a favorite track and get the needle to average at the 80dB zero "0" mark for each speaker you audition (you or the salesman adjust the volume).
3) I'm not sure I'd concern yourself with the 1st order crossover issue right now, since most likely you will crossong to a sub @80Hz anyway, right?
4) Since your basement walls are concrete, I might recommend you consider a Parametric EQ for the sub-out only channel of your HT processor. This is because you are likely to have some boomy bass peaks that you will want to reduce the SPL levels for.
For a Parametric EQ, I recommend a product from Behringer called the BFD 1124P for about $120. A great site that goes into detail about how to use a Parametric EQ in your room to reduce boomy bass peaks is
here it's a bit technical, but give it a try.
By the way, I also use RS Gold AV (75 Ohm) interconnects for both audio and video and think 12 gauge wire with spades is just fine (no need to buy anything more expensive) for speaker wire.</font>