Mileage...
Regarding mileage... the JDM engines have the same IF NOT BETTER fuel economy... take mine for example - I have a Civic RTi with a modified ZC motor (intake, ported/polished, 2.25 exhust system, catalytic converter removed, other 'make-stronger' bits and so forth) yet it still manages to do at least 500km to a tank (i think its about 44 litres) even when i'm nailing it all the time.
As for turbo cars being fast, i agree... but good gas mileage? I think we have differing opinions about what is good mileage...