If they are the same heads, then no need for an adapter ^^
The 3.4 engine fits in the 986 so we know there is room too !
No need for a laser scanner, it’s a human that designed it, humans like round number and geometrical disposition
It’s not hard to design, but won’t be cheap and won’t give big power gain if any.
I still think the intake manifolds on the 986 aren’t restrictions.
The small throttle body and tiny airbox are major restrictions, the rest is large enough for the stock cams/valves and displacement. And the closer you are to the valve the more you can mess the accoustic tuning of the intake and risk losing driveability :/