CAFE standards won't be why this engine would be produced, VW has enough low mileage engines in it's fleet, remember it owns Porsche. Another reason I highly doubt it will be built is economics, new engine design is not cheap, it's not just taking an existing engine lopping off two cylinders and making it work. As it is right now Porsche has been on a tear consolidating manufacturing, it's phasing out the MT with the PDK, which has managed to be on every platform, the new race cars will even have it. The new GT3 engine is based on the 9A1, just like the 991 and the 981, three sports platforms and one racing platform, the V6 is outsourced, the V8 is home bred, so why introduce a new expense in R&D when the flat sixes provide, economically, the solution. It's not MPGs either, a turbo flat four producing 350 horses isn't going to be significantly much more fuel efficient than the standard engines. The 981 series cars are already being delivered, now they're going to put four bangers? Also, if you're going to put them just on the CS or the BS, how do you justify running two engine lines for such LOW production cars? The 9A1 is used on all 9 series cars, now it would be a totally different engine. I just don't see it. Unless they source it from Subaru, I don't think Porsche will sink millions upon millions in R&D'ing an unneeded engine. I can't think of a logical reason for this engine to be produced.