Performance gains

[n2motorsports]

Hi, what are the expected performance gains for the following?  I've seen some numbers on GRM but feel free to chime in with your personal experience.  HP as in WHP.

air intake (k&n drop in)    1hp
ram air intake
test pipe (fake cat)  ?
exhaust cat-back     2hp
chip    3hp
headers?

for headers, I really like the idea of extrude honing these, but I'm not sure what kind of difference it'll make.

[gearheadE30]

* These are either what I have experiences or my humble guesses

Air intake-1hp maybe
ram air-probably nothing unless you are going REALLY fast. If you mean a cold air intake, they generally show negative power
test pipe-5hp or so, high RPM. Will sound like crap though
cat-back-2hp
headers-these cars already have headers, so nothing or almost nothing. Not sure what extrude honing would do, but I was under the impression that was usually used in castings.

[ecpreston]

ram air-probably nothing unless you are going REALLY fast.

yeah, I've seen a few good articles debunking the "ram-air" effect for a street car. Here's the first one that popped up, seems pretty complete:

http://forums.corvetteforum.com/showthread.php?t=1129295&highlight=ram+air&forum_id=1