Nissan suing Audi over Q

Nissan, who famously sued a guy named Nissan for the rights to a url address, is suing Audi over their use of the letter Q for their new SUV the Q7. While I don't think anyone will confuse the two, why is Audi using the Q at all. They have A and S right now. There are a few more letters left in the alphabet to choose from. And what does Q have to do with SUVs anyway? How about Y. Like "why do we care?" Anyone want to help Audi out with an alternative letter?