EGR valve...
 

I have a v6. but still i think the 4.6 has an EGR valve too.. okay, does this serve an important purpose? will deleting this increase HP? Tune required? Leave it alone? It seems retarted taking exhaust and running it thru the intake.. Opinions needed.

Leave it alone. It takes the unburned fuel from the exhaust and runs it through again. If you delete it, you'll likely lose mpg and power (granted not much)...but it's not worth messing with.

You won't loose power by deleting it, and no noticable loss in mpg. It may take a little bit more time for the car to warm up due to the hot gases not recirculating into the engine. You will need a tuner to turn it off correctly as the computer will think something is up. But you can cap it, buy the kit from VAP. If your not having a problem with it or have a need to delete it I would leave it alone. The EGR system is actually off a lot of the time anyway, it's not on at certain throttle positions and if the computer senses anything wrong with it, it turns it off.

Ahh,, so like say when my car first starts up thats why the CAI makes that strong SUCKING noise.. and after it warms up it quits.. weird how these things work..

I don't think that is why your CAI does that but when an engine warm up a lot of things are slightly different that when cold. Everything expands and moves as its heating up.

That's not the point of EGR. It's done to lower combustion temperatures in order to reduce NOx production. Most newer cars don't even come w/ it anymore. Plus, you will most likely gain mileage/power, especially w/ part-throttle driving since now the engine is burning a cleaner air/fuel mix. If mileage drops after removing it, it might be because the computer needs to be tuned to know it's not there. However, I'd only bother if you have the time and/or cash to delete it. Remember that you will fail inspection if they peak under the hood and the EGR valve isn't there.