I've fitted the R-spec MBC and it works fine, you don't need any other piece of kit apart from the MBC itself (and 2 cable ties).
I originally has it set at 12psi but have recently turned it down to 10psi due to fuel cut (problem solved).
As per the other responses, fit a boost gauge first and foremost and get used to the stock boost pattern. Fit the MBC fully closed and find a clear section of road where you can pull in and out of. Gradually (2 turns at a time) turn it up until you reach the desired boost level (12psi is a good mark to aim for). A half an hour of spirited driving should see you good in terms of getting the boost level right.
CJ