Hi rooker,
core i3 2120 is hardly 100-150 bucks costlier then 2100 and it is 3.3 as compared to 3.1. So its your call buddy.
Also radeon 7850 is a way to go. and IMO cx430v2 is ok
but dont take a risk. Atleast buy cx500/600 or Seasonic S12 520/620W for safer future and long running of components.
You can save some bucks in cabinet and invest in good psu. I will see you tomorrow as discussed