I agree with not getting a Klipsch sub. They make a decent sub, but a horrible value. Look at SVS, HSU and ED for subs. Get the best you can from any of those companies. Buying online will yield a much better sub for far less money. There are lots of options, but I'm assuming you're done with being overwhelmed.
Honestly, based on your 80/20 use habits, I wouldn't think you'll gain much by getting the 82's. The 62's have the exact same high frequency driver and only give up 1 db in sensitivity. The speakers are smaller and with a sub, I doubt you could ever tell a difference. The extra couple hundred bucks should go towards a sub. I wish I could tell you to apply it to the RC64 center, but I think its just too much where your budget is. The 62 will work just fine.
Something else to consider, you don't necessarily HAVE to use the reference line for surrounds. Using the synergy line (say the s20) will also save some coin for very little change in performance. BTW, I would never recommend anything but the reference for the mains and center, but you'll never tell the difference from your surrounds.
A pair of 62's, RC62, and S20's will be right around 2 grand. Spend the rest on a sub.
I wasn't SUPER impressed with the BWs you have, but then again, I personally don't love their highest end stuff. I actually really like the Klipsch stuff. It cracks me up to hear sales guys call the Klipsch's "Bright".. They can be for sure, but the reference line is much more refined than you might think. Some of the brightness is predisposed.
Like jinkjukieuua points out, the bws could work in your room, they're a fine speaker, but I do think you would need to add some wattage... Don't worry about an external amp for the Klipsch stuff, you won't need it. They'll probably never call for more than just a handful of watts.
