I think it would be more appropriate to say StarOffice 6.0 is made of OpenOffice 6.0 source code.
It's sorta like Mozilla and Netscape, mozilla is the opensource version, while Netscape is the "brand version".
Though StarOffice does come with a few things OpenOffice doesn't come with, such as a databse, and I think it has a few more added things like fonts, clipart, and spellcheckers.
Oh and of course, support 😉