[j.fro]

This is why I laugh when I look at the arrangement that some out of work practical Engineer did in his Garage, using a vacuum cleaner blower motor to blow over objects, in an attempt to design a component.

Ouch!

I think that is exactly what they did, how else can a:

2.7L 986 have 217 HP, ~80 HP per liter
3.2L 986 have 250 HP, ~78 HP per liter
3.4L 996 have 300 HP, ~88 HP per liter

I agree with this, and there is further evidence from the current 3.4 liter engines: 350HP in a 911, but only 315 in a Boxster S.