I'll try to speculate a little based on last years. Though, you'd definitely get better prices during the boxing day.
The processor price might go down a little, but not that much
The GPU at 249$ might get around 210$-220$ during the boxing day...not sure about black friday though.
The RAM/case and mobo would probably stay at that price
The PSU may or may not go quite lower...it depends on it's popularity. You could definitely get a 600W PSU for cheaper though.