If you want to delve into this farther, I have some, but I am far from an expert. You have to understand that a turbo (turbine - compressor) really is a device that based is upon efficientcy. Essentially, the turbo has a sweet spot the that the OEM utilizes. This is where the OEM will set the waste gate at and initiate de-fueling based on high boost pressure.
When the modding starts, you move out of this sweet spot. However, more air plus more fuel equals more power.
I feel that you should be concerned mostly with two things. First, when the turbo makes higher boost pressure it is at the expense of a higher boost air temperature. This equates literally to higher EGT's. Second, when the turbo makes higher boost it is a result of higher RPM's.
When talking turbo RPM, understand (my charts are at home so this is for example only) that lets say the turbo runs at 75,000 RPM to make 20 psi, it runs at 160,000 RPM to make 35 psi. What I am trying to illustrate is that the RPM increase vs boost increase is not linear, this is because the efficientcy drops.
Just keep in mind that the information above, is like the iceberg that the
Titannic struck. It is only a very small amount showing, but in my opinion, the part you can do something to avoid.
If you increase bombing, eventually you will hit another boost limit. Once again, consider it to be just the tip of the iceberg. Most will say 50 psi of boost, others will say 500 Hp. At any rate, at some piont the head gasket will not hold the combustion pressure the engine is generating. This is when people start talking about modifying the head, head bolts and the head gasket to hold the increased pressure.
Jim