Why turbo normalizer?

I"m still confused...
1) Why not just put a regular turbo on and agree to not over boost it?
2) If compression increases inside cylinder pressure about 8 times
wouldn't taking MP up to 30" cause a MUCH higher inside cylinder
pressure than 20" (its a mutiple scale). If the outside of the cylinder
is 20" its going to have a significantly higher difference in pressure
than running out the outside 20" in MP. I just don't see how a cylinder
could crack and stress relative to 30" when its only 20" outside. Isn't
the cabin of the space shuttle under more stress when in space than
when sitting on the ground at sea lever?

-Robert