Thanks, Andy. 4x20 mm plus new jets will be the next mod. And I hope to go on a dyno before and after the mod.

I now see the point about race pipes and engine power curve shape. I guess it will depend on how often I get on a track vs km's on the road. And $$$$'s! (sorry, no pund sign in my keyboard). In any case, Tyga power-up explanation is brilliant, and based not only in pipes, but also on the reed area. For road use, this mod seems pretty interesting.

Neal, I've decocked exhausts before with caustic soda, although I did not like the results. Is this your preferred method?