After-market replacement kit to temporarily bypass a vehicle's muffler silencer resonators to improve exhaust sound, performance, fuel economy and other characteristics

A replacement kit to enable a user to generate a desired audible sound levels from an engine of a motor vehicle, the motor vehicle provided with a factory catalytic converter positioned within an exhaust flow path between the engine and a factory muffler, the factory catalytic converter connected to the factory muffler through a factory pipe segment, the factory muffler having a downstream end fitted to a pipe section visible to the motor vehicle's exterior, the factory catalytic converter and factory pipe segment having been detached and removed from the motor vehicle for replacement, the replacement kit comprising:

• a. a replacement catalytic converter and a replacement pipe segment arranged for positioning within the exhaust flow path between the engine and the factory muffler to replace the detached and removed factory catalytic converter and factory pipe segment, the replacement catalytic converter having higher performance characteristics than the factory catalytic converter and having an upstream end for receiving exhaust gases from the engine and a downstream end;
• b. the replacement pipe segment having an upstream end detachably connected to the downstream end of the replacement catalytic converter, and a downstream end detachably connected to an upstream end of the factory muffler to direct the exhaust flow path through the factory muffler;
• and
• c. a bypass pipe segment including an upstream end arranged for attachment to the downstream end of either the factory catalytic converter or the replacement catalytic converter, and an exit end arranged for fitting to the pipe section visible to the motor vehicle's exterior when the factory muffler has been detached and removed from the motor vehicle.