Let freedom ring. The Library of Congress defined a few new exemptions to the Digital Millennium Copyright Act (DMCA) as part of its typical review process. The one we care about? Allowing people access to (and tune) a portion of the software that runs your car. This means that digitally tuning engines (increasingly popular given the complexity of turbocharged drivetrains) is fully protected under the law in the US. Good news given the fact that many automakers were attempting to define any digital manipulation as copyright infringement.
Source: Library of Congress / Exemption to Prohibition on Circumvention of Copyright Protection Systems for Access Control Technologies (PDF)