Pop-off valves

["Rodney L Wiggins" <rwiggins@clev.frb.org>]

     Greetings,
     
     Has anyone here had any experience with aftermarket pop-off valves. I 
     think Greddy makes one. I just love the sound they make. The car 
     already has a recirculation type bypass valve and I'm wondering if 
     they'll be any noticible gain (other than the cool rally-car noise on 
     high boost shifts). By the way the car is a (audi manufactured) porsche 
     951 (with weltmeister chip) . Sorry for the non-quattro post. You guys 
     (& gals?) were always very knowledgeable & helpfull with my Ur-q 
     questions.
     
     Thanks,
     Rod Wiggins