Shadorne - you raise a good point. Not sure about the 5500s. but the K2 9900s I heard at RMAF were pretty impressive.
Antonkk - You won't really know anything until you try them in your system and you may very well love them, if they are in good condition. I would be wary if the seller won't let you try them first. Depending upon the price, maybe you could offer to pay a small amount to be credited towards the purchase price if you decided to buy them, sort of like the Cable Company does? At least them he could see you are serious and that might change his attitude. Good luck.
Antonkk - You won't really know anything until you try them in your system and you may very well love them, if they are in good condition. I would be wary if the seller won't let you try them first. Depending upon the price, maybe you could offer to pay a small amount to be credited towards the purchase price if you decided to buy them, sort of like the Cable Company does? At least them he could see you are serious and that might change his attitude. Good luck.