to be honest I do not trust any aftermarket emissions manufacturer...I would buy used OEM before I went aftermarket. most of them put barely enough catalyst in to pass federal...and they all tell you this as seen here. some offer a whimsy 25K warrantyUpdate:
Just got a phone call from the dealer and was told the aftermarket catalytic converter was clogged causing the horrible hesitation. They had to drive the vehicle with the scanner and used a temp gun and was told it was 300 degrees hotter than it should have been. It just so happened that a recall was issued for the exhaust manifold cracking on 2015-2016 Outback's and Legacy's however they didn't want to cover it at first because I had already replaced my cracked manifold with an aftermarket one. Subaru agreed to cover the clogged aftermarket manifold with a factory one as long as they could have the aftermarket one to send back to Subaru??? I agreed but questioning why they want the manifold, I hope it is to contact Walker because that's what I wanted to do. For future reference do not buy the Walker aftermarket manifold the first one I had cracked and the second one clogged after 8-9k miles.