R_Rated

http://www.ipdplenums.com/

Controversial in terms of any real world gains... especially without a tune however >75% of the power from hardware in the factory powerkit comes from a revised intake plenum. The IPD plenum is far more robust and oem quality. Adding BMC filters will make barely marginal additional power but help a little on the midrange and improve sound mostly.

Many debates about these but mostly conjecture withe lack of quantifiable data.

JensenC4S

Very easy to install. Bumper does not need to come off, FYI.

erko1905

I think conventional wisdom would be ipd plenum plus some sort of a cat delete/high flow cat combined with a tune has to yield some power, since you are "opening up" both the intake and the exhaust side of the equation and amending the tune to get things in line w the hardware. It does seem uncommon though I agree I haven't seen much data either, I think unsurprisingly the NA Carrera doesn't attract the tuner crowd.

NVRANUF

You would think if there was actual verified independent data that quantifies the gain numbers the plenum manufacturers and resellers claim, they would be greeted by Porsche's modding community with open arms. Instead there are seem to be larger numbers of skeptics than there are accepters of plenums doing anything measurable.
They do look nice!