More power better economy possible?

[Zack12]

I've got a 04 forester 160k miles doing 21mpg seems low but planning a remap after I've changed a few bits. Is it possible to get more power and better mpg? I'm not wanting to sound like a fool when I'm talking to the mapper

[Tidgy]

Depends on car and mods tbh, standard vs mapped will see an improvement because mapper can lean the mix out off boost so will use less fuel.