I wouldn't get another file off of a random car. If anything, use a dhp 1.0 you can get off the powrtuner website until you learn how to scan and tune properly yourself. Make your own tune so you know whats changing or has changed.

I would download UvScan to scan. Then Eddies table modifier to do a bunch of maf tuning. Make small changes each time and flash it with powrtuner. Make sure to save the files in order so you can always go back to something if you don't like that change.