Those airbag steering wheels may be considered an explosive device because of the firing mechanism. And the CO2 or whatever cartridge may be considered an hazardous device too.
Check with the shippers, UPS, USPS,DHL , etc. to see how one would ship that restricted article . Also , even if it has been fired/blown , it may still be considered a restricted article. All of these shipping rules come under federal guidelines, rules and regulations. So If you ship it anyway and they find out, well you have broken a US Federal Law and they are not a too forgiving people to deal with.
With this bogus Patriot Act, well you definitely may have stepped into some
so watch out.