Id suggest getting/making a better reflector out of some metal and having the bulb horizontal, like this from my favourite grow cab ever:
Other than that small snag, It looks like a quality job. Also I dont think a PC fan will pull much air through all that pvc piping, you may have to invest in a a nice inline fan. Just run it for a day when the bulb gets there and monitor the temps carefully and go from there.
Big thumbs up from me