I can richen it by installing the PCIII. I just hate to do that if I don't have too. I was fairly sure about the white plug = too lean thing. Now if I can get a plug out short of pulling the tank. 
I'm glad someone mentioned this. Actualy, I thought I heard an occasional pop on previous occasions with the stock exhaust. But as mentioned, it's so difficult to hear that I probably wasn't noticing how often it was happenning.Actually, the popping was always there, you just couldn't hear it with the stock pipes.