QUOTE (Nick? @ Jan 10 2010, 07:23 PM)

Most FWD have Diffuser's its proven to work i guess
those are what you previously called 'turbo holes'. It's a pretty weak way to get the effect of a diffuser. In this application, I'm sure it's functional because he probably gutted everything that wasnt necessary.
In most other street applications, the fuel tank and all the cladding underneath the car don't even allow the air to hit the front side of the rear bumper, thus they are useless and quite frankly ugly.
And neil, you're partly right. The diffuser he is referring to is the GT/LM type that actually directs airflow to stabilize the car at high speeds, like this: