There has never been any official mention of DLC for Gran Turismo even 7 months after launch but now it appears that some may be on the way.
When speaking about the recent 1.10 update for the game Sony editor Guillaume Couturier said in response to a comment on the French PlayStation Blog;
Polyphony has already started with the new update, DLCs should follow.
A similar comment was also made on the European Playstation Blog;
I appreciate the frustration with regards to DLC but keep checking
back on the PlayStation Blog, there will be news in due course.
So does this mean that Sony are finally looking at releasing some DLC for Gran Turismo 5?