We've done testing with two local customers that were identical modifications (CAI and power pack tune) and found that stock for stock the PP was about 0.3 seconds faster, but once tuned they ran identical times down to the 0.00x time. The PP car has an Airaid, the non-PP car had an EPP. We then switched the intakes for giggles and saw no performance change at the track.
The non-PP customer did end up selling his car a week later, while the PP customer kept going. With further tune revisions and moving the shifting up a few hundred RPM higher (5800 vs 6100) we were able to keep the shifts out longer with a custom rescale of the VCT to hold power up top better, and got him down to 12.3s on E30 stock HPFP and then 12.0s with the addition of a XDI-EVO and GH intercooler.