You should perhaps double check that boost guage with a scanner if your running so much boost. I have heard stories about gauges being 2-3psi off, hate for that to be 20psi instead of 17.
Checked with GMTDScan, and it peaked at 17.11 once, around 16.5 rest of the time. At wot I would say that 95% of the time it stays well below 16. The gauge was dead on. When I get a clear idea of EGT I will try to decrease boost a bit, and see if the EGT changes to the worse.