Hello Lachezar,
welcome to our board.
Most people on here are able to read in english at least
My english is pretty rusted in, just excuse the grammar mistakes and stuff.
It is pretty easy to get a MK4 RHD (doesn´t matter if TT or NA) road legal in Germany.
There are companies which are offering this service, but thats expensive (calculate around 500€ for a stock TT and up to 1k till 1,5k for a heavily modified car).
Our user "Speedmaster" owns such a company (
http://www.rhd-speedmaster.de).
You can try it for yourself of course, should be slightly easy as you have an TT which was already sold in Germany.
All the paperwork is existing in the holy file rooms of the TÜV, you just need to know where
Some people over here did the "Vollabnahme" themselfs, they will post later on I guess.
Only thing which could make a problem is the fact, that you have an 98 Supra (all cars after 96 had to pass the Euro3 emission test if newly registered).
That Euro3 thing is the reason, why Toyota stopped importing MK4 (Mazda with RX-7 too) to Germany as it wouldn´t pass the test or the test itself was too expensive for the small number of cars being sold here.
But I think there is a possibility to get around that too, just wait for other answers or ask Speedmaster
