Yfz 450 Duncan racing? Curtis Sparks? ESR? B&B? TT/Flat Track?

I would go with alba. They got a kti you can do yourself, or for $550 they will build it for ya. just ship em your motor! so for around $1800 bucks you will get a fast motor!! Trust me i had them do it for me! Only thing is that they bore it to a 470 i think. dont know if thats illegal for the series you race in or not.