As usual a great post from BackPacker.....
Let's see if I can add something;
Keep in mind that a JAA PPL done in the USA is
exactly that, a JAA PPL done in the US.
Meaning that you have NO flight experience in Europe and you knowledge of charts and airspace is purely academic, if even that.
That means that you would realistically need some hours of training before you can fly in Germany. Add that to the cost ( 5-7 hrs or so local and a small cross country).
Another point:
All the JAA schools in the US are certified through the UK CAA. Which means that your ground school and study materials are all aimed towards flying in the UK. I am pretty sure that English charts and airspace are different from those in Germany.
You may want to get in touch with
AeronautX - Luftfahrtschule, Pilotenausbildung They can help you out with FAA > JAA conversions.
I would recommend to do your PPL and IR in the US then conversions in JAA country.