stlouistrucker
Like you I just completed this work and I am very happy with the new chirping alarm. My wife likes it very much as well. Cool feature if you didn't know is that if any of the doors or trunk is open it only beeps twice at locking to let you know something is not correct.
To answer your questions. The why is way beyond my knowledge. But I can tell you that the center funnel on my SRT empties out just to the drivers side of my transmission.
The foam piece that you have taken a picture of I found under my windshield wiper cowl stuck in a little plastic clamp molded into the cowl near the middle still in place. I'm guessing to help cut down on noise and vibration as the wind moves past.
Again just my observations hope I helped. I'm sorry I didn't take a picture of it while I was in there to show you where the foam piece goes but I think you will see it once you look under the cowl.