Porsche should have learned their lesson: Air restrictors can control hp, but they don't effect torque. This is one huge advantage that Corvette and other bigger engine opposition has had in the past (before Turbo).  Now with Turbo's (which are essentially torque multipliers) in most of the serious opposition (Ford and Ferrari), it seems to me that it would be a fools errand to try and compete with what has often been the smallest NA engine of the field.

I think the main drivers behind that decision (if they do take it) will be (as usual) money and marketing (dependent on what is planned for future GT3/2 cars).

Porsche of course, will claim they have seen something in the regulations that can provide them an advantage. They are usually very good at this, but....times they are a changing and regs will move in the direction that most want it to move.