Quote Originally Posted by GTScoob
Yes, you can tighten down the wastegate arm for quicker spool. It wont raise your boost but merely keep it shut for longer so that you get boost quicker. It can cause serious compressor surge or compressor stall on the turbo if you dont adjust it right.

Not sure how it would work without tuning either.
If the wastegate actuator is tightened, more boost will be required to open the wastegate. Thus the turbo will build more boost before it is relieved. I haven't heard about surge, but I do know some people who occasionally get spikes on cold days.