Agree with madmatt30. Overclocking may be your best bet here, but make sure your board can handle the extra power requirements. Purchasing an 8350 is going to get you one more CPU module, so you would have 4 modules instead of 3 (8 ALU cores VS 6, 4 splittable FPU cores VS 3,) but since the modules will be identical except in the default clock speeds, it will also net you more heat. IPC will remain the same.
Will this net you any performance? Depends on what you're doing. If you're not performing heavy multitasking with the system, using those last two ALUs and 1 FPU, probably not. How threaded is the software you run?
Your current 6300 should easily clock to the same speeds as any 8350 you could buy, provided your board supports it and your cooling is adequate, and the only benefit one chip can show over the other when not running heavily threaded tasks is clock speed.