Okay so I have an Alienware X51 R2, and I've been wanting to upgrade, and my card in mind was the Nvidia GTX 660. But recently I noticed the more expensive models of the X51 come shipped with the R9 270 and 270X. So I look up the price, and they're around the same as the 660, and meant to be a good bit better. I would like a graphics card upgrade that'd last me a few years, and I believe this is the one for me. However, I know it shall definitely require the 330w PSU upgrade, which I need to buy anyway, but will it require in special actions in the installation? Like, reversing fans and overclocking things or underclocking them. I can only find overclocked models of the 270X by the way, which I don't know if will work. I'm quite a novice at hardware and graphics cards, so I really need assistance. I know that the GTX 660 requires the 330w PSU but apart from that, you just pop the old one out, and put the new card in. But I want to know if the 270x will be the same way, or what I'd need to do. Thank you.

Current specs -

GTX 645 1GB graphics

i5 4440 quad core CPU (3.3GHz)

8GB RAM

1TB HDD

240w PSU (I know I'll need the 330 for the upgrade)