Eric/Steve 125 more 02 Cr125 advice please.

Eric/Steve have you tried comparing the engine performance with and without the reed spacer?Also on the powervalves there are some horizontal slits machined into the face of the valves-whats that all about?On the exhaust side i noticed honda have not put in the strange little lip just before where the manifold bolts to the cylinder-i remember reading if you remove the lip it loses 0.5hp so why isnt it there?Im going to keep the 02 exhaust manifold for now as once i open it up to the 01 size theres no going back.I will try to get good power using the 02 manifold and if i carnt then i will get the big drill and bits out:p thanks marcus.