Nice Work,

if you struggle getting the screws into the HDD rack see if you can get a thread tap from a hardware store, it should clean the threads out a treat and shouldnt damage your powder coat, you see them using them all the time on the likes of american chopper etc,

as for the fans black would be a nice contrast, it just depends on what white black balance you are going for. another alternative would be to paint them white if you dont like paint them black