The Dundon muffler is internally bigger than the stock Porsche part. It is also heavier at 26 lbs vs the stock 12.6 lbs.
The weight is going into the stronger construction and the welded internal baffles instead of the pressed together stock parts that break loose and rattle, then fracture the mufflers shell.
The stock side mufflers and diverter valves are heavy. They also heat soak the back of the car which the sensitive 9A1 engine hates.
The side mufflers are 22.4 lbs each compared to the 9 lbs Dundon cats and diverter valves.
The Dundon headers slip right in place.
Howard snugs the bolts down by hand at first till everything is in place and lined up.
Next Howard torques down the manifold bolts.
Next Howard bolts up the Dundon cats by their mounts and a V-Band clamp to the headers.