You certainly won't regret getting the i7 if you decide to do so in the end but the 8320 is and will be very decent for quite some time. Though if you absolutely want the best of the best then sell your current setup, re-use the cooler (just make sure that it has an 1150 compatible mounting plate) and grab that Gaming 7/4790k bundle. AFAIK, there's a nice cashback deal on Gigabyte/Devil's Canyon so you can shave 25 quid off the bill.