Porsche exhaust?

[SpikeSchumacher]

I have a 2 litre in my '72 1302 (Super Beetle) with BAS exhaust system. I want to modify it to run with a Porsche, or similar style, cat-back exhaust under the rear apron. Anyone tried this kind of modification or have any feedback on back pressure or lack thereof? Also,I am running dual 40mm Webers & CB Performance large valve heads.

Thanks,

Mathias