Servo motors are best for precise movements..look no further.. you can order them online..there are a variety of sites selling them..kits n spares is known to all..however they do take a few days before delivering the product..so you might want to search for a shop somewhere near your place.. you might want to check this link too –http://shop.sumeetinstruments.com/ .. i ordered a few things once from here…was spot on. Hope this was helpful