Need a quick answer

[GT40FIED]

Actually it does make sense...some designs are just better than others. And you don't need high velocity at lower rpms. Just look at your factory exhaust this way...it's like going jogging while inhaling through your mouth like normal and exhaling through a straw. Now...you can move more volume without seriously increasing or decreasing velocity. A SLIGHT increase in velocity is good since it will help evacuate the combustion chamber and leave fewer traces of the exhaust products and in some cases will also increase intake velocity as it creates a slight vacuum effect. HOWEVER, and this is where you and I disagree I believe, too much increase in volume and velocity will eliminate backpressure. Most people think of backpressure as a bad thing but it maintains low end torque. Not power...just torque and that's what gets your car moving. A small decrease in backpressure vs. stock is a good thing, but increasing it too much will seriously effect your low end grunt (and I know how you guys love the low end torque those moster D and B series motors make). The design is the main thing here. Whether it's 4-2-1 or 4-1, if the design is poor or the primary and/or collector size is off it's not going to help. If they're too big or too small then you're no better off than when you started.