Ckrikos -
I love the splitter under the GT3/AerokitII front bumper. I was lucky that the guy who I bought the bumper from had already added it because he paid $417 just for the splitter per his receipts. It is the 2002-2005 996 Carrera GT3 front spolier/lip (Porsche part#996-505-986-92-01C).
I have also seen a slightly smaller version that does not extend to the sides, but I don't know the part number (pic below on a 911).
heliguy -
Yes, that is a Turbo-style inlet that you spotted (I didn't have them on yet when the front picture was taken). I think the single horizontal bar matches well with the horizontal bars in the outer grill areas of the GT3 front bumper.