1) GTX770:
I have a GTX680 which is basically the same thing (ASUS model. Love it.) I play every game at 60FPS. For games like Crysis 3, Far Cry 3, Metro 2033/LL I had to spend a bit of time finding the optimal settings though.
I also force Adaptive VSYNC on for many games. For example, in Crysis 3 I tweak the quality settings so I drop below 60FPS roughly 10% of the time. When that happens I get a small amount of screen tearing (VSYNC automatically turned off with Adaptive VSync). If screen tearing starts getting too frequent I drop a few quality settings to stay synched at 60FPS more often.
2) Wi-Fi:
The Z87 Sabertooth does not support PCI, only the new PCIe. As said, a regular Ethernet cable is "best" however wireless has improved...