APR stainless steel, mandrel bent, cat and downpipe
replacement for the S4 is $1499.
APR's S4 Cat and Downpipe Exhaust replaces the
the exhaust from the turbochargers to behind the lower factory catalytic
converters. The system removes the factory pre-cats right off of
the turbocharger and includes six separate components. Included
are the two pipes off of each turbocharger, a set of pipes with
catalytic converters, and a set of test pipes without cats. With
TIG welding, fully stainless construction, and CNC'ed hangers, you
will not find a higher quality system on the market.