I just used seafoam carbon cleaner in my 1.8t tsi. It has 49000 on it. No codes. I just thought that I would clean them. Followed directions and it only puffed a big cloud once when I drove it like I stole it. Some very little smoke after that, but quickly went a way. I'm sure it was the bat out of hell driving 😂. I had an engine code saying bank one O2 sensor reading rich/lean. Cleared it and hasn't came back on yet after about 25-30 miles of spirited driving in sport mode. Idk if it's just my imagination. But I hear the turbo whistle more now. And it seems to go better when you get on it, hard😄it might just be my mind playing tricks on me.