A case of Corporate rip off: Gamestop

I own a PS3. The 80gig MGS4 bundle, the last model with backwards compatibility (B/c). Seeing as how I never really use the B/c and my electric bill is outrageously high I decided maybe it was time to trade up to the Ps3 slim. (It's suppose to use 40% less power) So being a smart shopper I decided to do some research and see how much I could sell my Ps3 for. Here are the specifics.

1) It is the 80gig MGS4 Ps3.
2) It has a backwards compatibility emulator in it, so it plays all ps2 and ps1 games.
3) I have installed a 320gig hard drive (HDD) in it. (This is well within Sony's warranty, in fact they actually encourage and explain how to change HDD in the instructions).
4) The system itself is in perfect condition, no scratches, dust, or chips in the system.
5) And I have a Brand New Playstation Move Sports Champion Bundle. (Gift from a friend) unopened.

I could easily get $350 dollars off Ebay for this, but I decided to call Gamestop to see how much they would give me. Here's what Gamestop said.

1) They would give me $120 dollars for the system.
2) $120 dollars is including backwards compatibility feature. (Backwards compatibility does not increase the price of the system.[I called back later and just said I had a Ps3 with no backwards compatibility, the price was the same])
3) They said I have to re-install the original 80gig HDD as the 3rd party one I had violated the warranty.
4) The man said he would have to charge me a refurbishing fee of $20 dollars to replace the outer shell of the system. (After telling him it was in perfect condition he said "It's company policy."
5) The man also told me that "Gamestop does not take new unopened merchandise." I would have to open the Sports champion bundle in which case I would get $20 dollars for the Wand, $20 for the eye, and $10 for the game.

Over all. I would receive $150 dollars from Gamestop for my 320 gig Backwards Compatible Ps3 with New Unopened PS Move sports champion bundle. That's about as much BS as I've ever heard.
350+ on Ebay or 150 from Gamestop. I think my choice is clear.