Start the car up and have it running. Then take out the floor pannel to look at the ecu. Then look at the light on the side of the ecu... if it is on while the engine is running then the ecu is locked in diagnosis mode and will make the car slower than shit! Turn off the car and turn the screw all the way the other way and then go for a ride and hold on. This is just my theory here...but I have helped 3 different people with this problem...they're TT's were running slower than NA's and they had no idea why. Remember the diagnosis light should be off when engine is running. Check TECH under ecu diagnosis to see what Im talking about if your unfamilar with it.
