Adrien, I have the same unit that thyname has, and, like him, I got it at a SUBSTANTIAL discount. I would never have paid full price for it (way out of my budget). I don't believe, and would never claim, that it makes one bit of difference in how my system sounds. I didn't buy it for that reason. It does, however, have several features that I really like, and I think it looks sexy. Those are two perfectly valid reasons for my purchase.
So, If you like the Panamax, for whatever reason, by all means hang on to it. Just don't hang on to it because you think it will make a difference in how your system sounds. If it's not important to you, take that puppy back and save your father-in-law some money.
