Awhile back I bought a 2000 a6 2.7t 6 speed. Finally had the time to get it running good had nasty miss fire. Now that it's running good I realize it's not a stock tune how can I tell what tune is in it . Guy I got it from I figured out the hard way had no clue what he was doing with this car. Want to make sure all needed mods are done and done right to get the most from the tune