The Fabspeed Porsche 996 Carrera Competition Link Pipe X-Pipe (1999-2004) features: 
 
Dramatically improve mid/high end power by replacing the catalytic converters with a free-flowing x-pipe while adding aggressive sports car sound and throttle response. For track and off-road use only and is used by many Rolex Grand Am race teams as well as PCA/POC and HPDE drivers.     
SOUND:
This system will provide a significant increase in volume over the factory system, while also smoothing out the exhaust note.
POWER:
We dyno developed this system to make the most possible power in the top of the power band. Above 3500rpm you will experience huge power gains. We saw 33 whp and 41 ft-lbs on our Dynojet.
FEATURES:
Fits all Porsche 996 Carrera vehicles 1998-2004
Improves horsepower and torque by 33 whp and 41 ft-lbs
Saves 25 lbs from the rear of the vehicle
For track and off-road use only
Adds an aggressive exhaust tone
Constructed from mandrel bent T304L stainless steel
Simple DIY bolt-on installation, no cutting or welding required
All Fabspeed performance products are backed by the Fabspeed Lifetime Warranty
NOTE: The Catbypass X-Pipe provides dramatic power increases in the mid to high end of the RPM range.  Street drivers may notice a small torque loss at low RPM's, which is why we recommend the Sportcat X-Pipe for street applications.  Please also bear in mind that this system does not include catalytic converters, so the Check Engine Light (CEL) will most likely be triggered. This is not an indication of any actual issue with the engine, and does not prevent normal vehicle operation.