Why is it that any other car manufacturer gives it's new models
an engine with more horsepower?

Only Subaru seems to be the exception:
http://tinyurl.com/32twsyt

This engine should be the standard in any Subaru model, including
the Impreza.

 

Well it is the NA 2.5ltr engine, more torque and better fuel economy, still 170bhp though (remembering the old 2ltr turbo's were only 177bhp on these).

Tony