Sandys spares downpipes

[solorider]

looking at the design of the pipes the reason is the pipes are a 4 into 2 into 1 which will give a increase in the midrange where a 4 into 1 will give a top end power increase,that is if they have been designed properly,but you will probably have a slightly less top end power output,but to be honest how often do you use the upper part of the rev range?