I just ordered a pair of used but new in open box SM65's speakers from Electronics Expo on Amazon. I think the price with shipping at 645 dollars was okay. I just hope I won't have any trouble with them and regret not buying brand new ones from Best Buy for 900.
But I've got two questions. I wonder how important it will be to have a powerfull center and surround speakers to match the 65's. Would for example the sound experience be significantly lowered by using the lower end of the Definitive line such as the promonitor 800's? Or will the 65's as main speakers elevate the whole system to a level where the other speakers blend in aggreably?
The other question I have is if anyone has a good tip on how to pack theese speakers without the carton in a soft duffel bag that will be checked in as luggage for an airplane flight.
For the center, either match them (another SM65 would be optimal; a PC2000 work work well) or go with the "phantom center" approach. (In situations where there is one viewer who can always sit in the "sweet spot," sometimes phantom center is better than almost anything. And it's free to try.)
Definitely don't go with a lesser speaker for the center channel. For surrounds, sure, as long as you're not listening to a lot of surround music, you can use something like a PC800.
I'm not touching your question about packing them. I've seen too many bags getting thrown around by airline baggage handlers.