Very interesting thread.
Nice cfd, however i think you actually need to make everything correct with wheels and flow into engine since that changes alot.
From the decklid extension I dont see that he got any improvement. Most likely alot of air will pressure bellow the decklid. However with an diffuser you might have another result
Its intresting with these vortexes that separates air and also with different irregularity that causes air to slow down so it more easily follow edge etc. It works for golfballs atleast
