The cat converter started making a grinding noise from where the insulating wrap had degraded so I started movign on a replacement. According to receipts, this was a Catco unit I'd bought a couple of years ago (I thought I'd bought a Magnaflow but whatever), and is sold as a high-flow unit with larger cells. Searching around there are a few complaints about Catco and rattling so I figured I would try an OEM-like direct-fit unit from Maremont. The thing seems well constructed, it has the right shape and doesn't need any adapters welded on, and the shop says installation was pretty simple. All good.
Unfortunately I've lost all power above a certain level. For example if I'm doing 60 in OD down the boulevard it doesn't matter how much gas I give there is no responsiveness, no change in speed or any noticeable change in power output. With the Catco unit the car would accelerate and I could pass the slowpoke easily, now I am the slowpoke. It still has power from a standstill, but everything above that is pretty much wet noodle. Sucks!