Stick with the 6300 , a decent $20 cooler like the raijintek aidos, & a 4ghz base overclock which is easily doable on that board.
You'll be very close to 8350 performance levels then irregardless of the loss of 2 threads.
8320e would be pointless as you'll be stuck at stock clocks.
On that board the 6300 will perform better once overclocked even slightly.