Do I need a tax number in the USA?

No, you don't have to worry about local sales tax, as kdglobalusa acts as the seller. Additionally, you don't need a US company. SPACEGOATS buys your goods in Germany under retention of title and, together with kdglobalusa, takes care of importing your goods. For more information about importing, please see the 'Who is responsible for importing my goods into the USA?' tab.