The original manufacturer's exhaust system on your car is designed to meet the federal emissions regulations as well as to muffle sound. Unfortunately, part of the way that it does those things is by restricting airflow. That restriction robs your engine of power. If you've been thinking about upgrading your car's exhaust system to regain some of that engine power, there are some things you need to think about. Here's a look at some of the things you'll need to consider as you decide on your new exhaust upgrade.