The 645MG is too slow for an ST. You would be much better off with the Hitec 625MG. It is 39.99 from tower.. HOWEVER.. if you do a search for "Duratrax bulk" you will get 1 result.. it will be a duratrax metal geared servo.. it is the Hitec 625mg with the duratrax name slapped on it.. for 29.99.