Avis - Audi TT in Germany

I have an upcoming rental in Germany, booking is for a premium BMW 3 series. Question : do Avis have Audi TT on their german fleet and what are the chances for an upgrade from BMW 3 to Audi TT ? Ofcourse I am ready to pay for the upgrade ;-)

Where are you planning to rent?
I find Avis tend to use merc and audi more then BMW so you probably won't even get a 3 series. Been over more then 2 years since I've had a BMW in Germany.
Phone up the actual rental office and see if they can get one in. Avis do I find tend to have a safe fleet. Only once have I been offered a scirocco which I thought was very cool.
I end up with a c-class coupe if I ask for something different to a premium saloon.

Thanks Martin, based on your recommendation I called Avis, they said I should expect something from this list VW Passat,BMW 3,Audi A4,A5 , Merc C... They said they do not have TT on their fleet at that station

Thanks again for your help