how could i improve gameplay without spending more
You just need to add a case that you would like. It doesn't have to be a big case.
Now; the reasons for why I chose what i chose:
- RAM: You can save few dollars on it. If you are taking a graphics card (so you're not using the on board graphics) it wouldn't matter much if your RAM speed is any faster than 1333 MHz.
- PSU: The PSU doesn't take more power than it's required, so don't worry about your bills going up (considering only PSU). Also, such a strong PSU would let you upgrade to whatever you like (new GPU in 3 years? - probably won't need it since you have a GTX 770)
- CPU: It is actually very good to have an unlocked processor and plus it's as strong as it gets for this generation (for gaming).
- HDD: It's a Barracuda + the price - had 4 of them - never failed.
- MOBO: Unlocked chipset. Also It's the Z97 - well it wouldn't make much difference if you would want to put a newer processor (on a Z87), because you just have to probably do a BIOS update, but after all it's better to have it done so you won't screw up flashing.
I would also like to point out that even if you would include a case in this price range - you would still have some money to upgrade for some dust filters etc. (if the case doesn't have them)
That would by all.