RE: New MB Engine...
What do you have currently? personally i'd say, get a zenoah 26 and a jetpro + an airfilter and you'll be very happy. if you really wanna get more out of it, it seems you'd be better off with the CY... so maybe just get the CY, buy yourself a jetpro pipe.. see what you think, if you want more take your pick out of a 27 or 29