I went to the dealership today to ask about 08 changes to the TT and what I was told made a lot of sense.
I asked if there were going to be any changes to the lights or any other exterior component of the car. Told them that I had heard there were going to be some minor changes.
What they said was;
None of the components being changed were common to the TT.
Example, parking lights on non turbo 997 are not common with the TT. The non turbo 997 is getting some design changes to the parking lights that will not be shared with the TT.
I am also convinced that this will apply to any changes with the tail lights as well.

 

FWIW, my dealer told me exactly the same thing (here in the Bay Area). Only Porsche knows for sure but it sounds about right to me. I think the turbo 09 model will inherit the new led taillights and other minor changes (direct injection?)