034 Motorsport Diverter (Bypass) Valve, OEM 710N Audi S4/RS4 B5
 
OEM "710N" bypass valve with reinforced rubber diaphragm for longer use than other plastic valves.  This is the best factory plastic valve ever produced.
 
These are a budget route when looking to replace or upgrade your stock valve, but are still plastic valves that degrade with the extreme temperatures and pressures of the turbo engine.  Bosch no longer makes this valve but we offer equal "OEM" grade versions (not a cheap Chinese imitation valve) from Kayser and others, quality and function is identical and unchanged.
AUDI S4 B5 2.7T
Audi RS4 B5 2.7T
Audi A6 C5 2.7T