Thanks for the wishes Mates!

@ViperDriver: Thanks for your explanation. In this case, I will think about this solution, too. It seem it really work with a kid in the rear!

@Carlos: Thanks for sharing the picture - this help a lot and gives confidence that the space is enough. I could also think about getting the back-seat cushions of the car out, this would give a couple of cm more space in height and deep.

@Stefan: Didnt know that you are expecting a new Rennteamer soon, too! Congratulations - when is the date - is it a girl or a boy?

@Darius: Did you use a Maxi Cosi/Baby-Car-Seat in the rear? How does it fit?

Many thanks again, this helps a lot! I also will buy a Maxi Cosi today and try to fit it in my Convertible. I really think about getting a Targa as it seems it has more space in the back and that the rear-window helps for fitting more stuff in the rear!