The normal terraclean will more than likely clean your fuel lines and exhaust back, maybe whatever else the treatment fluid passes through.
But.....
They do a special type for the TFSI engine, how good it is, i'm not to sure, have heard of people having misfires, then having the new type of terraclean done, now no misfires !
Would be good to hear if anyone else has had the new type of terraclean done?
I'll maybe have a go at it and see if there is any difference after!
It can only do some cleaning.