Is the cat ment to be broken in?? This new one I have had about 90 miles on it today before I failed and did worse than the old one overall... However it failed 15mph and passed 25 mph, just like before. I'm running the ngk v power plugs. Would you guys recommend bosch plugs? I'm also thinking of running "guaranteed to pass smog", the fuel additive. I have never used race fuel, I just run 91 octane. I'm out of ideas. So ANY help is appreciated. Thanx