Don't get so excited, man. no need for those caps.
I didn't check with pcpartpicker, but last I checked the 6300 was more expensive. maybe there's a discount on it right now. but the fact is he most likely won't use those 2 cores, you gotta admit that.
About the price differene between the 290 and 270, yeah I didn't realise It's as much as that, but there's always a possibility of getting a used one with warranty.