In the exhaust system you have a series of catalytic converters, gaskets, muffler, and electronic sensors.  From the daily rigors of the car heating up and cooling down, the exhaust system will have a replacement life span.  The most common issues are exhaust leaks, sensors going bad, and catalytic converts going out (on higher mileage vehicles).  This can range from not as efficient gas mileage, car not running properly, to not being able to smog the vehicle.  LIC Motorsports has state of the art diagnostic tools to quickly and efficiently find out what is causing the issue(s) and properly fix it in a timely manner.