The best prices I've seen for the Mach .26 is $139 at Leisure. As for the SH .28, like Tex said, it sells all day on E-Bay for $129 to $139. Haven't done much research on the XTM 24.7. I did read somewhere that all 3 of these engines are made by the same manufacturer... If you do go with the Mach .26, you are limited to a 16 tooth clutchbell with the 49 tooth spur. You can fit a 17 or possibly a 18 tooth bell with the 47 tooth spur. If you want a bigger clutchbell, you need an XTM 24.7 backplate. (The stock Mach backplate is oversized)