Cobbzzor

These questions may have been asked but didn't find anything in my searching. So I just recently flashed my 04 sti to stage-1 93 oct with a recently acquired Cobb AccessPORT. So far I have noticed a difference in the "power band" with it being smoother. So everything seems to be running well and sounding normal, did one live data for boost and doing a second to third gear pull i hit 16.2psi. So my main concern about the car is reliability, it's my daily driver and I can't have it go down. So since the AP does data logging, what should I be logging to make sure that nothing with the new flash is harming my car? That being my main question, however when I just pulled into my parking spot after driving around town a little today, I popped the hood to just take a listen. Everything was sounding normal but then I heard something different, it was a very very quiet inconsistent knock. It would come and go and could barely be hard over the usual subaru "tick". So I shut it down, went inside for 5-10 and came back out. I then checked my oil, which was just fine, and started it back up. The sound was gone. So I don't know if i was crazy or not, but what could cause a really quiet knock after flashing to stage-1?

Well I took a video before flashing stage-1 to show my valve tick, and I just took another video. Both were taken with my droid so the quality isn't the greatest.

Before: http://profile.imageshack.us/user/co...l/#543/dkm.mp4

After: http://profile.imageshack.us/user/co...8/75069561.mp4 (sounds more prominent in the beginning of the vid)

What could be causing this noise and how serious is this?