I'm not trying to argue that 930 intake is superior, but Brian has a good point - Anyone who uses the Carrera intake needs to do something about the port size.
And I bet 99.999% of them ended up enlarging the port on the head. The engine becomes a much better air pump; hence more power (assuming everything else is the same).
But now its a much more costly route...
87 930 K27HFS/B&B/Twin-Plug... Megasquirted