I think you would be surprised how well an MC21 will perform with just a sprinkling of HRC bits, ie, jet kit, loom, stuffers, pod filters, ( ram air ), or open carbs, and a decent set of pipes, I had this set up on my 21 with good results, I also think if you go chucking NF5 stuff at it, as Andy said it starts getting complicated to set up, and with the big HP comes the too frequent rebuilds, and you are then getting into RS250 territory, but you probably know all this, good luck whichever way you go.
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