Share '105 good for CX?'

i'm currently trying to build up a stigmata for CX racing and overall trail bashing. i thought about trying to piece together drivetrain bits or just getting a decent group with most of the stuff already included like this one for instance: all shimano 105 5700: STI shifters rear der front der chain cassette - gearing of my choice crankset - 50/34 bottom bracket all this for $440. good price?…