I've seen the indicator scoop, and the bonnet duct scoop too.
The indicator one is a great idea, but it doesn't look like it gives much air-flow. I was thinking of making one but a bit bulgier (new word). I also doubt it can be made road legal without making the indicator surround fully reflective (aren't cracked headlamps/indicator glass mot failures?).
I've looked too at taking half the area of the bonnet scoop and ducting it over the air filter, or dropping it into a box like the se nissan one (like rally cars still do). Half is then left for general engine cooling and oil coolers. I mocked a crap one up (cardboard, don't laugh), just to see if my tmic could be retained, eerm, it can't :-D . But is sounds like steve has this one covered.
I've also ideas for proper brake ducts (one of mine is still on the nurburgring
), ducts to flow onto turbo, integral front splitter, oil sump duct, rear splitter, window lips (stop wind noise), flared front wings (only subtley, but enough to get a duct out the back like on an escort cos), reversed side vents (think this has been done) etc etc. So much to do !
Going to start with headlamp scoop as always good for drag/track/daytime.
What should the duct taper down to, inch-wise?