Hi Nate,
hmmm...still not sure, non vented does flow well as Gav said but is'nt there a vented one that is identical in dimensions to the non vented one appart from the vents?
I like the BRE spook spoiler for a car thats been subtley modified re the body just like the one in the pic with the chic, just wheels and a neat spoiler, nice and clean and neat.
The g-nose certainly would give the car a unique look but I still reckon they stick out too much, not that I don't like the look but non a huge fan.