Boost doesn't destroy internals, detonation is a bigger engine killer than anything. You can run as much boost as you like, as long you accept the fact that if you detonate, the motor will go bang in an instant.
From the compressor map you can see that the tdo5-16g peak efficiency (77%) is in the 6psi to 18psi range. This would be the optimum range. However you can run as high as 28psi and still have decent enough efficiency, only a 5% drop off, in performance. On the road the car was able to achieve 7psi by 3000rpm without a proper tune, so I suspect depending on tune we should be able to run between 15psi and 20psi to achieve the goal.