JJ/Flash,
What is marginal in your opinion? A tenth of a hp? To think they are all exactly the same is silly. Yes, they are close, but equal? No. When a guy can afford that last tenth, wouldn't he be a fool to not try to find it?
Based on extensive dyno AND track testing, I can say .10 is marginal. I have seen karts with .3 less win big over those with more. Handling trumps HP and with 5 dyno pulls an engine will vary by .10 pretty easily. People who talk about chasing .001 are people who don't really know what makes a difference at the track and are usually chasing ghosts with greenbacks. That said, I do everything I can to get the best performing motor I can for peace of mind and the personal challenge. However, I am not losing sleep when one motor is .2 more than another. I also find almost every 206 I work with is within .2 of each other. I don't do anywhere near the numbers as Brian, Jimbo, or Baker, but I have tested dozens (getting close to hundreds) of 206's and that is the window I find. I have also tested everyone of these guys engines and find they are usually in that window as well.
Right on JJ!