I agree with facemelter. Rotton eggs means the cat is WORKING, and that you are probably running a little too rich. I just put in new cats and they smell like eggs after I get on the gas, and I know it is running a little too rich, I'm still trying to tune the thing (I have a carb). Plugged cats mean loss of power and higher emissions, since you are running really clean, I highly doubt there is anything wrong with the cats, just a tuning issue you need to find.