[Biturbos4] air leaks / turbo overspin

[TStifler]

Does a boost gauge help identify a small air leak ? What else can help you know the turbo(s) are over spinning ?  I suspected I had a boost leak only after I started hearing a very slight turbo whistle when the engine was cold - after never hearing the turbo's at all for the 1st 25k miles.  The VAG didn't show any codes - but when I made the awe pressure tester  I found a major leaker down on the drivers side turbo - an "o" ring or seal, the dealer said - fixed under warranty : )  
But, I envision a boost gauge only telling if the leak is so big that peak boost is not attainable, while small leaks might allow the turbo(s) to overspin yet reach full boost, and appear ok on the boost gauge.  Maybe I need to throw the pressure checker on there every few months ? What else shows the small leaks ?  
I enjoy this board guys - keep it flowing!
TStif  - fearing my KO3's are no longer like new :(