Seems a bit messed up when the pipe you use on the road has to be swapped for a quieter one to use on a racetrack.Well, I put the original pipe back on the MT-09 today, mainly because I want to try it out at Castle Combe and they have very strict noise limits there - 105 Db (which doesn't sound too bad) but at 75% redline revs (which is much higher than most other tracks). The last time I was there, on a road bike only day, 10 bikes failed, including a new R1 with the standard pipe.
Anyway, I took it out for a test ride, and although the evidence from the speedo was that I was riding just as quickly, it just seems to have lost most of its character. All I could hear was the wind and some gear noise. So maybe that goes some way to answering Sdrio's original question - we all want our bikes to have that little extra something, and having it make a "nice" (to us) noise is one sure way of doing that.
I think the Akra will be going back on once it's had its track test!