I have 2008 with Stainless Works 1.875" headers with High flow cats... 0420. 0430, 0153 I believe as its been a very long time since I had the rear o2's ON. I tried the foulers and experimented with them for a bit and I got 400 miles on the passenger side with no codes what so ever, but never went any furthwer with it. Will be experimenting with the stock cats sreal soon....
i gave the antifoulers a shot as well. ran them double-stacked with some steel wool, but it didn't seem to work. but check this out: when i saw that they weren't working i just left them in there. some time down the line, (it's hard to say how much time / miles passed, it must have been 6 months or so), i remember there were a few days in which i was actually passing the emissions self-check. every time i would turn the key to "on" in the morning, instead of hearing the bell and seeing the MIL blink, it would simply go off. this only happened a handful of times and then went back to the usual self-check fails. i don't know why it happened. a few months ago i went to remove the antifoulers, and saw that the steel wool had corroded substantially. i'm thinking that maybe the corrosion process had started the second i got the antifoulers in there, and kept going until getting the ball of steel wool to just the "right" density, which is when i may have passed the emissions self-check. as the corrosion process continued, whatever magical conditions were created in there for those few days changed, and i was right back at square 1, failing the emissions self-test.
this was the only time i passed the emissions self-check since getting headers. i'm thinking that when i have time i'll try loading the antifoulers with more steel wool and timing the mileage to see if it happens again.