I just picked up one of the 21-5k motors and wanting to know the optimal setup in my 8ight buggy. My plans are... OD99 Plug, Dynamite 086 pipe, Novarossi short header. I am having issues deciding which restrictor to install and get the best fuel millage with this setup. On my old P5 I ran the 8 restrictor, wondering if the same results apply on this motor.