The DZSL SLC always gets better then 47mpg during regular driving and can get 55+ when I stay out of the boost. I really enjoy driving I95 at a fast pace and getting 50-52 while getting 900+ miles per tank. I don't think the maazine guy belived me when I told him what I had gotten for mileage. But it really does get suberb mileage and fun factor performance.
The other TDI Corrado is averaging 45mpg during my regular driving and has not seen much I95 traffic. It has a smaller tank so I won't be seeing any 900-1,000 tanks
The engines are from different generation TDIs so the technology is different and thus get different mileage estimates.