To answer your question, no it doesn't make it a duel exhaust set up. The exhaust on our trucks come with 2 cats. The TRD exaust will just replace the existing one from behind the second cat to the back(cat-back system). It is a direct bolt on and requires no drilling or welding. It sounds much nicer in my opinion and "should" add some performance. Besides a dual exhaust is not recommended for our trucks.mycirus said:Just a quick question, does this make it a dual exhast setup. I see that it has 2 cats. Do you have pics?