I'm using a late 2014 13" Air (4gb / 128gb) MBA, which up to now has been great at everything I've thrown at it. But now I'm throwing stuff at it that it doesn't like. I've started using FCP X and Pixelmator, which work reasonably well if they are the only applications running, but if I want to listen to music, run an external drive or do anything that requires power, it all slooooooows down. I will need to use FCP more and more, for more intensive projects than I am now, so I think I'll need to swap for an MBP. My question is, if i want to run FCP, Pixelmator, Outlook, iTunes and Onedrive all at the same time am I going to need i5/8gb/128gb or i7/16gb/512gb or something in between. I'd prefer to keep to the least expensive option, so what is it?