I know it sounds strange, but when I use 93 octane gas, my car seems to quiet down. Do you think I might have clogged cats? I know I have the stock H pipe, but it never fails, when I use a lower octane, my car sounds louder. Maybe I'm nuts. I have noticed extreme sluggishness lately. Probably because I am used to the car and need some mods. Gear, O/R Pipe, Chip, and T/A sound good. Now I need a couple of grand!