I doubt the relationship is that simple. I think HFC failure is more related to the associated mods, tuning, and driving style changes that are associated with the HFC addition.

For example, these people are more likely to have other bolt-ons, forced induction, performed some level of tuning and ECU modification, are more likely to run race gas, may drive in trackdays/races, etc etc etc. All of these can lead to situations where cats can 'see' extreme driving conditions, incomplete fuel burn and detonation, higher engine temps...

...all leading to failure.

On a side note, Berk posted in a different thread that they use Magnaflow cores and suggests that these are higher quality cores than those in other HFC options. Is it just me, or is Magnaflow more often associated with inexpensive products and lower quality? I don't think top-of-the-line when I hear about Magnaflow anything.

Im kinda in the same boat as you there, Ive never heard of them as a top of the line thing but who knows maybe they are. I do know that HJS cats from Germany are top of the line cats. I had a full TBE from Milltek on my last car and they used 200 cell HJS cats, I would get a cel light once every three months but the exhaust was about 2 grand for the full one.

theres a guy on the evo x forums that had his hfc fail, piece broke off and clogged his exhaust flow. in the end when they figured out what happened with his car he went from a little under 300whp to above 400whp.

I have never had any issues with Magnaflow. Maybe things have changed, but back in the early 2000s they were regarded pretty highly in terms of quality. I know the kit I bought for my Mustang was nicely done... though every Flowmaster-loving Mustang driver referred to them as Magnajunk.

chiming in way late but i blew my my left cat yesterday does anybody know what the insides of an invidia gemini muffler look like? worried its clogged