PorKen

With my '89 with the supercharger the benefit is a quiet idle and a neighbor friendly part throttle.

I have a theory that it improves response with heavy throttle at low rpms on my '88 manual, but have never dyno'ed it to find out. Low rpm response always feels like it improves when switching from a X-pipe to the factory cats with smaller down pipes. My theory is the valves keep the X-pipe gas speed proportional to manifold vacuum.

jwbeck17

So what are the best steps to take with this modification? @PorKen , do you sell this cat replacement mod or is this something I would look to have built locally? I really have never delved into muffler mods before.

Gary Knox

Jason,

When the weather warms a bit, and you want to take a 'westerly trip', let's arrange an opportunity for you to drive the Aston and/or SL55 to experience the effect with those engines (V12 and supercharged V8)..

Helga might like to visit her old 'stomping grounds'!

Gary