Originally Posted by Disco Dean
If this was such a big issue the aftermarket exhaust industry and can industry would be non-existant. I know there is a lot of fashion and hype about that but in most cases a full exhaust will add hp without changing mixtures on a modern ECU bike. It of course changes the airflow and the tuning but the ECU accommodates for that appropriately in modern bikes. Maybe not bikes that are 15 or more years old but the R1200 for the most part (it is only my understanding) is not affected for mixture - It is affected and shows performance gains with better air flow (filters) =more oxygen and better exhaust flow = less back pressure more flow - easier to push that out the back end.
There must be some mid-range effects of intake and exhaust tuning on this bike. And it is certainly possible for tuning to effect the mid range (though admittedly I don't have any data on that effect on the R1150). I say that because the R1150RT and the R1150GS have much different intake tubes--for what reason other than tuning the intake?