I just ordered a DSLR camera which besides taking great photos it also shoots video at 4k.. I'm looking for a macbook to eventually edit and export these videos. I'm also not looking to break the bank for this purchase. What kind of horsepower do i need to run Final cut pro and work with 4k videos without much lag? Will a macbook air do the trick or do i have to go directly to the pro? I'm also open to refurbs and past year models. Thanks in advance!