Geoff
you do get 4 branch manifolds on RR's that have a 2 piece heat shroud that bolts together and hides the manifolds but the manifolds themselves dont have equal lenth primary's and I think that is what you are after. 4 into 1 is good for revs and power, 4 into 2 into 1 is better for low end grunt n torque
Exhausts are a science on there own and like everything else you only get what you pay for.