I guess I could spend a little more if it means getting to 5ghz.
Remember what anort3 said. Getting to 5Ghz isn't
even a guarantee, so don't count your chickens...
I still say you shouldn't be so hung up on 5Ghz anyway. It's a nice number for e-peen status, but that's literally all it is. 4.5 on a 3930K is amazingly fast, and more than you'll need for a long time (possibly for as long as you have the system).
Just think about it. Do you really need