From Criteriongames.com:

The Top 10 problems reported by you have been fixed, these are:

• PS3 game can crash when a player is taken down and the player that has performed the Takedown leaves the game.
• The game indefinitely displays "Connecting to Paradise City Servers" if it's having problems communicating with the rebroadcast server.
• Disconnecting the controller before a race begins can mean that race timings can be manipulated with players who didn't cross the line first being awarded the win.
• Repeatedly joining and leaving a game with 8 players can cause the game to hang.
• Hammering the A (360) or X (PS3) after unlocking a car can cause the game to hang.
• East Crawford and Watt St achievements cannot be achieved if the player goes online and sets road rules before attempting them.
• Audio distortion when using 5.1 / DTS and looking back at the car.
• Enhanced 360 streaming performance stops instances where the game seems to pause for a second or so.
• Total time driven in player stats would stick at 145 hours.
• VoIP connection problems with 8 player games. This is now live on the Paradise City servers.

The update also adds the following game experience enhancements:

• We fixed Head-on Takedowns as these seemed generally unfair and unrealistic. Unfair low speed Takedowns have now been eradicated.
• Increase online race timer timeout so players have a greater chance of finishing the race.
• Fix drifting bug when drifting and boosting. There wasn't any real control on the brake so players would grind around the walls of the corners. Giving you all better control of the car.
• Stabbing the boost has too much of a jerky behaviour in the car handling, when in Stunt Run.
• Surround sound fix - Centre speaker was 4dB louder, ruining the mix. The speech has now been positioned correctly.
• Increase the # of search results returned for online games.
• Increase Picture Paradise timer so it doesn't kick in so quickly.
• Post event ticker commentary is not now displayed for disconnected players.
• Show player the number of Complete Challenges easily by listing X/50 in the Challenges menu.

Other high priority issues that have been fixed:

• Instances where Barrel rolls were not registering correctly in Stunt Run.
• Takedowns online were not counting towards the Total Takedowns.
• Some instances where Revenge Rivalries desync & don't get fixed until players are updated online.
• Some instance where the Host couldn't change the game access if the game was created through an invite.
• Online challenge issues where the challenge couldn't be completed if it was started at the exact time that a player left the game.
• Incorrect rivalry updates when European players played against English or Japanese players. Online connection issues.
• Rich presence on 360 didn't change correctly when there is a change in the game parameters.
• Instances where Friends were not being displayed on the mini map.
• Some online race start points face the players in the wrong direction.