diverter blow off valve

two things here that i would like some input on: 1) does anybody in the LA area know how to change the boost on a 2002 1.8T gti?i would like to make it faster but i don't know how to change it myself. 2) i want to get either a blowoff valve or a diverter. What are the differences between the...

Hello,... i got forge DV it says forge on it .. my friend told me something must be wrong since i cant hear the sound TSSS when i shift gear.. but the car seems to run fine and everything, the silver shiny thing isn't that the DV and correctly installed?