I am heading to the dyno over the weekend to make a couple runs with and without the side pipes back-to-back, no tuning between runs. I want to see how much restriction there is on the standard pipe.
I spoke with Reg, he was told me to expect 2% hp loss. If that's the case, may not be worth new pipes, (9 hp for $2,000) I will post the results.
I did see these new Backdraft pipes - you can remove the baffling - very interesting...
Side pipe