Buying a used gaming system.

Hello, I am considering a used gaming system and I need advice. The offer is $800 for a complete package monitor, desktop, etc.


Here is the link for the exact parts: http://pcpartpicker.com/ca/p/krUD


Everything is in good condition except the monitor which has scratches on the bezel but not the screen.

*Is it worth the $800
*Would it be able to play modern games on high settings with a decent fps
*If I sli with a second gtx card would it play games (bf3) on highest with >60 fps



Thanks