As above. An FX 8320 is essentially an underclocked 8350 - with a simple multiplier bump you can get 8350 speeds out of an 8320, for less money and usually you don't even need to touch the voltages. So an 8320 is basically a cheaper 8350.
If you dont want to overclock go with the 8350, it will give better performance out of the box at stock settings.
If you are going to OC then i see no reason to get the 8350 since most 8320's can be OC'ed to 4ghz quite easily.
My 8320 is currently at 4.2ghz with a slight undervolt at 1.275v.