I said "really tramples". The 3750K is ~10% faster,runs hotter and overclocks less. He'd need the 3770K to really outclass the 2500K.
And it's kinda scary too Temp/Volt/CPU speed wise as seen in this image from Anandhttp://images.anandtech.com/doci/5763/4.4%20GHz,%20Vary%20Voltage_575px.png
That was using a similar cooler to mine. Intel's AIO Watercooler. My 2500K has never seen more than 65c(IBT 5 pass @ 4.7Ghz 1.3v)
There is no tangible benefit he would see in games by getting the 3750K. And the money saved could be spent on a better motherboard or an aftermarket cooler.