I think Dan Kyle compared the three I mentioned, and I think it was on this forum, way back when. I don't remember the hp figures. I do know that with a custom tuned map in my
PCIII and an Arata pipe, my 929 puts out 146 hp (I got a strong one) and my friend's 954 with the same mods is 145. I didn't dyno it stock, but with a generic map/Arata it was 138.
Different dynos will give different numbers, as will the same dyno on a different day, so that can explain the wide range of claims. The main thing is to see an improvement in the smoothness of the curve and top hp on your bike comparing it before and after a custom tune. The top hp really doesn't matter; a smooth curve with the proper air:fuel ratio throughout the entire rpm range does.