So the 2-1 is really a wasted design on the R/X? But does make me wonder how MM claim the 6bhp they list. But also the routing with clutch cables and brake fluid do like tight, and I wonder how they cope with heat?

cable & brake fluid are not a issue... had the MM on my XTR for 4 years..
yer gain 60mm of ground clearance.. so lowered mine 40mm still have
more than with the low pipes..
as far as HP goes.... the standard bike is unable to use what Mr yamaha
gave it....



..

Is it more the cats in the end cans sapping power that can be produced?

Don't think wasted design is the right term,the bottom line the only way to find out is buy one and see for yourself,no matter how good mine looked the way it ran was absolutely pants,not badly but differently and I didn't like it.

If you have a stock bike no matter what you fit will be better.