lots of tuners do this type of 'box-tune' pre-tested and programmed ECU (with safety AND performance in mind) - I'm just surprised it took me 9 years to figure this out for the Mazda6 (after I sold it!)
hopefully there are some good experiences here and everyone will be tuned :)
I sold my Mazda6 this past year, but we acquired a Miata...
it seems these guys can tune the ECU for more power/torque..
anyone have experience with them?