You could subscribe to the Audiogon and/or Orion Blue-books. Or simply check the 'Completed Listings' section on Ebay to get a handle on prices.
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Too low on #2, too high on #3. #1 and #4 seem fair, but you may wait for the right buyer for #4. #5 a little high, #6 perhaps a bit high, but you may have better luck with #6 on craigslist, IMHO subs are expensive to ship and unless they are special like the MA you may have trouble finding a market. You'll probably want a local sale on the MLs as well.
There is another alternative, let the market decide by running an Audiogon auction. That way, you know that they are sold at the end of the auction period as well.