Places like NAPA or Advance Auto have it, I would imagine most major auto parts stores should carry it.

 

.030 gasket create a little bit extra compression?

 

That would depend on a few things. First what is your deck height. Remember you want to keep a good squish, not too tight or to large. You will only gain a slight increase in C/R but could lose some ability to seal non-paralel surfaces.

 

Do you use The "Oil-Fix" (the little brass pieces) with the cometic gaskets?

 

no need too.

 

GSXR is right, properly done with clean, parralel surfaces and proper torque you should not have any leaks if you let your engine warm up before getting on it.