8350 vs. 8320

should i get the 8350 for $160? or the 8320 for $140? which is a better deal? how to the processors differ in matter of performance?

the 8350 will overclock better, that is the only difference

It is only a difference of clock speed. The 8350s are higher binned chips and that usually will translate to a slightly higher OCing parts but most 8320s will OC to 8350 speeds or higher. 

Usually the 8320 is a better deal when the 8350 is retailing for $199 but at $160 I'd prob go with that.