Well.. I did not touched my Wastegate on my stock Greddy kit, and look at my Dyno Sheets! I didn't get boost up to 0.2 bar= less than 3 psi!

 

Can be normal. The greddy kit is set @ 4-5 psi from factory...
Normally the fuel system can supply enough for 6 psi. So you can tighten the arm (sometimes it rattles) You need to make it shorter and get a boost gauge (wideband is very nice, but also expencive) a a/f gauge can show if you are rich or not...but it can fool you (narrow band (oem) O2 sensor doesn't react good @ our wanted air/fuel ratio's.