I know I've looked into it a little bit. Its hard to make them look right on the '05-'09 cars IMHO, the headlight housing is pretty large, and empty except for the reflector. A web designer buddy of mine referred to it as 'negative space'. With too much space, you get a weird effect, like eyeballs in a bare skull.

If you look at cars with OEM projectors and large housings, you'll notice they have integrated turn signals (look at the 2010+ stangs), metal accents, etc to break up the space and make it look more interesting. I think if you can get it right, the car will look really sharp & unique. If you don't, I think it'll look a little odd.

I'm not sure how much you've looked into it already, but try http://www.theretrofitsource.com/

they have some good info under "Buyer's Guide"

 

It would be nice, but they just don't look right IMO

-Nick C.

 

I... I kinda like that one. It looks like an eye of a Transformer... and I sorta kinda can see it on my car.

As far as negative space... yes. They already have that. So much black plastic under clear plastic, with just the lil' reflector inside all that...

And after seeing them painted, they look even weirder to me.

Just my $.02 on it.