Installed the Perrin intake w/ a Perrin downpipe and I felt a big difference in the low end and the car felt slightly sluggest around 4-5k then more power up top. The sluggishness was because the car was running lean between 4-5k rpms. I was seeing in the 16:1 range. I uninstalled it and the car's a/f's are nice a rice and the car runs smoother. Pissed cause now i have a intake sitting around until I can go get a tune.
if you plan on going with the AP and a PERRIN custom map, you will need to buy the PERRIN CAI. I know this for a fact, as I made the mistake of purchasing a K&N short ram and PERRIN told me they cannot produce a map for it.
my setup- PERRIN CAI, PERRIN Turboback exhaust, Accessport with PERRIN map tuned to 17.5 psi, making around 260 hp on an 08 wrx.