What some people do (AND I DO NOT RECOMMEND THIS AS IT IS AGAINST THE LAW, AND SHOULD ONLY BE FOR SHOW CARS) is they put heatshields over a testpipe to make it look like a cat.

Heatshields like this:
http://www.prostreetonline.com/pso/p...uctsku=PSI-CHS

once again, this is againt the law, and should only be used to replace broken heatshields on your catalytic converter. But for show cars that want that stock look when their car is raised, this would be it. OFF ROAD USE ONLY!!