If you are not a good tuner your type 4 of 9 will not make good low end. If you are a good tuner , your dry pipe setup will make more power than a B Pipe .,bottom /mid/and top end . Period.
I call BS. Just looking at the coupler diameter of the pipes (B and 4 or 9) you can see that the B will let more combustion out quicker. Which leads to more brap out of the hole which no tuner can do without a lot of CC's IMO on a drypipe.
4's and 9's completely suck for anyone in this forum. Period. I don't care how much you put behind them...if you bolt a B on to the same set up the B will crush the 4 or 9 out of the hole. Even if its only by 10 feet it is still way better for us.