Order up a Retina MacBook Pro and you'll likely be confronted with a gravelly message about how the SSD is "built into the computer" and not user-upgradeable. As it turns out, that's not quite true -- so long as you're prepared to ignore a whole bunch of other warnings written inside the chassis itself, iFixit has shown how to remove the factory drive and now OWC has a new SSD to replace it with. The only downside is the cost: at $580, OWC's 480GB Mercury Aura Pro is actually more expensive than Apple's official 512GB upgrade. In an effort to sweeten the deal, OWC is offering those who buy before September 30th a compact USB 3.0 enclosure to make use of the freed-up drive. Alternatively, you may want to wait for prices to drop or for OWC to offer an even bigger capacity with better cost / benefits.