You don't understand what I'm saying....The more area you have before the Y the better....Just like Long tube headers have a flatter torque curve so would this setup....At least that's the way John Lingenfelter's book reads....Like I said I would rather have a x-pipe myself but a single pipe going over the rear end (as long as that's just about as far as it goes) would have the same effect....The more exhaust pulse going through a single pipe creates a scavaging effect from the differences in pressure allowing more upper RPM horsepower and still having the low RPM torque of a full exaust....BUT I would think that the shorter the single pipe the better AND two cats will slow down the pulses less THEREFORE allowing more of a diffence in pressure and a better scavaging effect on top of the obviously better flow characteristics....I'm sure that a single high flow cat works great I've see it done, but I think that the DUAL (just for you aklim )setup would be much better for a high horse street car....Not disagreeing with you necessarily....I just keep getting responses from people with single cats, and while that input is appreciated, I haven't heard from anyone with duel cats, and like them OR even hate them but for another reason other than they rattled....But thank you for your input everyone, I value the thoughts of everyone