I run two OS-25SX on my twinstar and it is everything i want and more i like the extra, it runs great and them fx are such nice running engines, i had 32sx on it but i put them onto the c-160 and i bought two of the 25fx and i would not have gone any other way i mean you pay about the same price why not get a little more power but i am sure that either of the engines are nice on the twinstar i like that as they are light and run great. rollie