If you ask 50 5B owners more then likely You will get at least 30 different opinions. I have found with nitro a lot has to do with personal preference, driving style and so on. I just wish I could afford to buy 4 or five different exhaust systems where I could be my own judge.
As far as dyno test they are a good guide line but not the bottom line.
Being I was a motorcycle mechanic for over 35 years I have a lot of experience with dynos. I would set a motorcycle for peak performance on the dyno then take it out and ride it and many but not all the time you would have to make adjustments which would contradict the dyno.[X(]
Wonder if they will ever make a exhuast for 1/5 scale with a cut out like they used when I did my short time go kart racing years ago. On two strokes they would have a lever that you would pull once you had the engine wound out and it was like hitting another gear. It was like taking off the pipe while running and putting on another one. Going from a torque pipe to a top end pipe. [X(]