Dude, your going to be spending a bit to get 300HP at the wheels from the twin set-up, but hey if you want to try then go for it.
You will want to put a performance catback exhaust system on it to start with, probably a larger intercooler, larger fuel pump, maybe some modification to the turbo's to make them flow more, enlarge the waste gate on the primary turbo to handle more boost and hold it steady, Billsy does something with the ECV that apparently minimises VOD, Best getting some form of CAI whether it be an off the shelf package ($$$) or Hirisk style DIY home made jobby, and to top it all off you would definatly want a good tune.