down tube back pressure.
 

I have a 2006 Audi A3 2.0T FSI.
i want my car to look stock but still want performance. I was thinking about placing a wastegate on the down tube to spill at high RPMs reducing back pressure. i know its gonna make it LOUD! when it opens.
does anyone know...
how much back pressure is present at max throttle?
how much the stock exhaust flows in cubic feet per minute, max?
and what is the maximum flow capability of this engine?

any insight appreciated.