Buy direct from Amsoil by the case. That is what I do. Much cheaper than from a cycle shop. Don't buy auto synthetic for your motorcycle though as it contains friction modifiers that can cause wet clutches to slip (like a Busa's). Some folks will swear it does not matter but I will not risk it and I have done lots of research into the matter. Not in my bike - only 10W40 Amsoil full sythetic motorcycle specific. Check out Amsoil.com and find out for yourself.