There are definitely some things you can change.
- Get an i5 instead of an i7. They are identical except for Hyperthreading, which games can't take advantage of.
- Get one high-powered graphics card instead of two low-powered ones in Crossfire. Games don't support low-power crossfire very well.
- Get 8gb of RAM instead of 16. 16 isn't necessary for gaming.
- You'll need to find the model of your power supply to make sure it is compatible with the new parts. Old ones won't support the newest generation of Intel processors and they might not have the amps required to power the video cards.