Originally posted by 98EX
Yes it is good to have some backpreasure and I do believe that you will lose some with all those, but also remember that our motors are not the best in the lower RPM band, the upper end is where our motors live and that is where this helps the most.
It is never good to have backpressure. This is a myth stemmed from loss of exhaust velocity during the low end when moving to larger piping.
Backpressure is essentially resistance to positive flow, which is never a good thing.