I wouldn't worry about exchanging. I would worry about pretty much... everything being new. Unless you want to go with Haswell instead of Skylake to save the DDR3, which leaves you less room to possibly upgrade later. You can certainly save some things like the case, the PSU until it dies... but virtually everything else is going to be new. You're talking about a new GPU, a new CPU, which requires a new motherboard, which may or may not require new RAM.
All that being said, your computer should just be hitting some minor bottlenecks now, and there shouldn't be all that many as of right now. I would grab a slightly better cooler (h7 or h5) and ride that out. On air, you should be able to get a mild overclock on your CPU. Say, 4.3, 4.4GHz motherboard allowing. And the 480 if you need the better GPU. Would definitely take a 480 over a 380.