Hello - Hot Rods to a Civic Si lots of ?'s

So I've had 9 mustangs, ragining in years. I have pulled motors, tranny's etc, about done it all when it comes those cars. I understand the egine and the tolerances it can handle HP/TQ wise. With this Honda I know nothing.

Here is my main question:
When Ford puts out a 5.0 with 412 HP/390 TQ they build the rest of the car
(theoretically) to withstand that kind of power, and probably a 10-15% increase. I can say a new 5.0 with 9 pds of boost would run on all stock parts for a long time.

How is it that people are boosting these Si's, either turbo or blower, with up to 10 psi ( in some cases even more) and claiming the car is a realiable daily driver? I just can't see Honda producing a car with 201 HP and designing the axles, clutch, tranny etc to withstand such an increase in performance?
People are telling me I can run a turbo get 400 at the wheels and the stock compents (minus a clutch) will not only hold but last?

I mean 9 psi on a 11:1 compression motor just seems like a disater in my V8 head....
I need schooling.

Thanks! Look forward to hanging around here.

P.S. What is/are the weak link in this car (2013 Si)
I assume the pistons are not forged nor the rods?