[Logic]

Originally Posted by Vman455

Gee, if only there were a way to measure aerodynamic pressures on your own car instead of all this guessing and speculation.

Gee thx for the links.
BUT:
One does want somewhere to start your investigations before you go as far as designing and building an exhaust system.
You haven't dashed out with and angle grinder, welder, bender, some pipe and a pressure meter have you..?