Read very closly the info in this link.
But what is not explained is with a MBC ( Manual boost controler) There is not a very smooth power curve. It is a fast way to set higher boost very cheaply. The other and better ways will range from $75 for a n75j valve $300 to $500 for a chip and $300 to $500 for an electronic boost controler like the Greddy profect B spec 2 or better controling Apexi SuperAVC-R http://www.apexi-usa.com/electronics_savcr.asp
My favorite at this stage was the APR 93oct program combined with a N75j (Spikes at 19-20 psi).In the spring I am getting a front mount .When it gets installed I will then turn down the waste gate to get more boost at redline were power mostly drops off.