Technically they are illegal in this country as they plug into your Ipod and transmit the signal as a short wavelength FM signal, which you have to have a licence to do, although Ive never heard of anyone being arrested for it. The sound quality will be comparable to a poor quality FM signal, you can get a connects2 adaptor to allow you to charge and command the Ipod using the factory fitted mk3 radio although this will require you to do away with your CD changer if you have one fitted