The tail creates a high pressure area at the engine grill which does help force more air into the engine compartment. Without the tail the area around the engine grill is a low pressure area which means it's actually wanting to suck air out of the engine compartment. So with the tail you do get more air/cooling. I think I've heard a couple of people on the board report 10-15* difference in average engine temps after adding a tail. (sounds like free HP to me)
I wouldn't think that a wing would be as good for the cooling as a tail. Then if you are looking for intercoolers there's the problem of getting them to fit without the tail. Not easy to do, but has been done.
If you want to know about the aero affects of tails go here
major effect of the Ducktail is to reduce drag!.
Downforce
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Steve
'08 Boxster RS60 Spyder #0099/1960
- never named a car before, but this is Charlotte.
'88 targa
SOLD 2004 - gone but not forgotten