Is it possible to find out who made the tuned file? Is there a signature that could give us a clue?

I have a friend who just bought a Golf GTI mk4 (1. the guy that sold it claimed it had 220HP. there were no reciepts in the car from the tuning company, he didn`t know what company tuned it, and I cant find any tuners here in Norway that have 220Hp tunes for this car..

It runs stock DV, stock turbo, stock exhaust and stock inj, so I find it hard to believe this car has a stage 2 chip.. 

try to read it out. Then take a hex-editor and open the file in it, and search for plain text.
Most tuners leave a 'hint'  or 'spam' in their chips.

220bhp is quite alot for such a car on a fully stock config. Better dyno it, or do the vcds-dyno thing.
That will tell +/- what it has as of power.

scroll-on as the english translation is halfway down on the website :

http://www.whoopsie.de/home/doku.php?id=software:obddyno

Have fun logging !!!   If you do it correctly in 3'rd or 4'th gear, you get pretty accurate dynoplots.

Cheers,

PvL