They can take it from you if the courts find the name to be misleading to the public (aka, people think your site is theirs). You could always update their site saying you have no affiliation with armadillo brand speakers to protect yourself. You could then suggest they make an offer for the site.
Most companies will bully people into giving up a site for free. As long as you follow the rules and have nothing that would imply you're pretending to be them, you should be ok, but there is a slight chance that fighting them will have you in court. Maybe someone here with more experience in this scenario would help with their opinion.