Differences between DP's?
 

What is the difference between a regular DP like the AMS widemouth and the ETS open dump? I may be thinking of this the wrong way, but wouldn't an open dump like the ETS be kind of like an exhaust leak. Could someone educate me here between the differences?

In the manner you asked the question, open dumps are for internally gated turbos. Only the waste gate flow is dumped to atmosphere rather than being introduced to the main exhaust flow leaving the turbine. HP/TQ gains are said to benefit from open dumps(use the search button) but also increases exhaust sound while over/at tuned boost levels. Stock turbos for the 8/9/x are internally gated. When moving to a larger frame turbo t3/t4 most are not internally gated. Non-gated turbos require a ewg (external waste gate) plumbed into the exhaust manifold. Hope that helps.

Now that I actually re-read your post the information I gave was for o2 housings or DPs with integrated o2 housings.

If you live in a state that has strict inspection/emissions standards you may run into an issue running any open dump downpipe. Anything that vents to atmosphere, prior your cat could cause an emissions failure. Something to keep in mind :)