Is there any added horsepower with the TRD exhaust?

Check here, there might be something about it.
http://www.scionlife.com/forums/viewtopic.php?t=15870&postdays=0&postorder=asc&start=0

If not, try going to search and type in what your looking for. This topis has been talked about before, i just cant find the thread.

I couldn't find it either. That;s why I asked.

This is my opinion on the xB TRD exhaust.

I have no technical data, but my seat of the pants impression is no. I had one when I first bought my xB back in September, to me it FAR less low end power and MAYBE a SLIGHT bit more on the very top end..SLIGHT. Other than that it was just plain loud inside @ freeway speeds.

I have the AEM intake and had it on at the same time.

Think about the way you drive your car, it's mostly low end power that you use and very little if any true WOT situations where all these exhausts are supposedly making more power for you

If you want my opinion, the stock exhaust does a good job on the low end power, and a fair job on the top end power. A good all around choice, just put a nice tip on it and save yourself $300.