Yea I've read that before....larger exhaust does slow down exhaust (as noted in that post, also noted, you dont' want to slow it down too much) but I was speaking about an engine that has stock manifolds "choking" power away....you can go too big yes....but I was talking more about when your being choked....that larger exhaust piping slows down the exhaust velocity.....again...you dont' want it to slow down to much....but in general...a larger exhaust is more "free flowing", doesn't necessarily flow faster....but more freely....