Almost 4 years ago, I had my G12 on a powerbench.
I also have a Mistral High Rise pipe like Pete. Mine is the carbon version.
We started at 92 Hp and a major dip in his torque curve.
After several runs, try outs, open BMC airfilter set up, without Db killer, we finally had an amazing 112 Hp
And a much, much better torque curve.
The original Mistral DB killer also killed more than 10 Hp...
After getting hints about making a better db killer, I made one myself:
My G12 runs like hell and sounds nice.