My PC is on its way and should arrive tomorrow. My case has one intake and one exhaust fan (Corsair 5000D) and am thinking I'd quite like to put three RGB fans at the front (obviously to make it go faster). I'm assuming that if I just go to "Upgrade this order" and buy the three Corsair LL120 fans, they simply send them out and I can install them myself? Seems PCS are way cheaper than anywhere else for them. How does it work for other upgrades down the line? Do PCS want the PC sent back to them so they can upgrade it? Can we do it ourselves? Where is the line before it invalidates the warranty? Obviously slapping in a few fans is no big deal but is different to changing out a motherboard, which I'd be perfectly fine doing myself but just speaking hypothetically.