Look at your wastegate actuator , the rod that hooks to the waste gate flapper, if it is one solid rod, then u have a stock waste gate actuator. If it is two pieces, one threaded with a lock nut, then you should be able to spin the end of the rod and shorten or lengthen the rod, thats an adjustable waste gate actuator. which one do you have?
If you have an adjustable waste gate, you gotta be very careful, only shorten it one half turn at a time then test it by rolling into throttle getting to wot gradually, any knock you gotta immediately lift off throttle, and access the chip to adjust your fuel targets. Depending on the version of the TT chip it should give you access to adding fuel, and adjusting spark, best plan is to go to turbotweeks website and download instructions for tuning with that chip. please tell me you have a knock guage or a scanmaster, cause you need something to alert you when you have knock and something to keep an eye on your O2 sensor readings so you don't go lean.
I hope this info helps but don't take it as a "how to" you need to check your waste gate actuator, and go to turbotweeks website and download or copy the tuning instructions for that chip, it should have a version # on it 5.x or 6.x the instructions will tell you how to access the chips adjustable features. I highly recommend you do not turn up the boost until you get the chip instructions and understand how to go into the chip and adjust the settings, oh and i'm pretty sure you need a scanmaster to do that so you can see the settings. I told you if you want to raise the boost to 14 or more its proabably gonna cost some money, and some stuff gets expensive love my buick but it is a money pit.