I'm going to tell you it's going to cost way more than double the $220, since you're skeptical and would get hung up on the install, I'm sure.

If you're a capable mechanic and don't have any hiccups, you should be able to do it for $275~.

Also; there are plenty of ways to get around it. One guy already mentioned the fake cat. And the EGR can be tuned out, along with the o2 codes.