When you add boost you raise the compression in the engine, and need higher octane for higher boost to prevent detonation.
Example a 9.0:1 stock compression and add 16 lbs of boost you raised the compression of that engine to 18.8:1

That is why the srt and the n/a has two different stock compression ratios, the srt has a lower compression so it can handle more boost.
So a 11.0:1 engine stock if a turbo was added and 10 lbs of boost then the two engines would have roughly the same compression and need the same requirements to run that the 9.0:1 engine with 16 lbs of boost would need.
The 14.7 or 1 bar or 1 atmosphere makes a difference on the effeciency of the engine. After 1 atmosphere of pressure then the engine stats using more more to make the boost than it did at .5 atmospheric pressure.
5-7 psi in a engine and it can last longer than a N/A engine due to the engine is not doing work to suck in the air but rather have it available.