The latest version of Gran Turismo 5, version 2.04, is now available. Weighing in at 79MB in size, the update focuses on fixing a wide range of software issues and bugs. Here’s the complete list of changes as announced by Polyphony Digital:

-Improved the performance of online races to provide a better racing experience. However, please note that using voice chat with 12 or more players can reduce screen refresh intervals.
-Reduced wobbling of the screen when using the Chase view (The Chase view is when the car is viewed from the rear during races and replays, selected by using the SELECT button).
-Electric cars (opponent cars and your cars in B-Spec) will now pit-in automatically to recharge the battery.
-Reduced the amount of steering pull when using force feedback steering wheel controllers in banks on courses such as the Special Stage Route X Oval.
-When driving formula cars using the Logitech steering wheel controllers, the initial force feedback amount has been lessened and adjusted to make it easier to drive in a straight line.
-Fixed an issue where speedometer, race position and best lap time info are sometimes not displayed on the 2nd player side in 2P Battle Mode.
-Fixed an issue where exhaust sound is heard even after switching from a combustion engine car to an electric car within the same online race.
-Fixed an issue where if the game is started without signing in online and then saved, the cars and courses included in the Racing Car Pack and Course Pack would become unusable.
-Fixed an issue where electric cars would not recharge in the pit and become immobile.
-Fixed an issue where when the oil of the Toyota Prius was changed in GT Auto, the motor ceased to function correctly.
-Improved the force feedback of the Guillemot Thrustmaster T500 RS, where the 10 level force feedback adjustment (especially when using the X2010 and X2011) was not working effectively. Also improved a condition where it was difficult to drive in the intended path.

http://www.gtplanet.net/gran-turismo-5-update-2-04-fixes-many-issues-available-now/

Looks like just mainly small bug fixes.... but the big one is:

Improved the performance of online races to provide a better racing experience. However, please note that using voice chat with 12 or more players can reduce screen refresh intervals.

No, it means you get exclusive commentary rights!