Has anyone ever tried anything like these?

http://www.bigdaddiesgarage.com/mini-cat-cel-fix.html

 

They should offer a nice solution to CEL lights created by failing converters.
Usually folks distance the O2s as much as they possibly can to keep the numbers fed to the ECM stable and not too rich.
This having a catalytic core can help fool the sensor without too big off a spacer.

 

I have z1’s high flow cats which already have extensions built in and I also added another extension on top of that and it’s still on. I have cleaned the throttle bodies and Maf sensor in the past and it went out long enough to get my sticker. Might try that again but I’d like a more permanent solution because the stock cats are very expensive and I can’t find any used ones.