I would advise against putting anything not designed for the hood, on the hood. Most of the stuff I used is butyl rubber, which is really sticky, but...
I've had the same issue (including death at a stop), happens months apart. No codes, then about 2 months later an O2 code (one was dead and making me...
I did, with the race exhaust it was quite loud inside. I've since built a silencer to insert in the muffler, and it's really nice now but still keeps...