I traded my 2013 TT for a 2013 TTS with 4300 miles on it. I noticed that from a start it feels a little sluggish until about 3k rpm, which my TT never did. Since the car came from Long Beach, and I live in Mile High Denver, should the ECM have to be re-flashed? If the dealer had put Regular gas instead of Premium in it could that cause this (they SHOULD know better). After reading about the S mode button, I wondered if that could affect drivability somehow on or off? Anybody have any ideas? Thanks!