Playing online in GT5 is all good until someone brings a super-charged car to the race and smokes everyone in the race. To address the issue Polyphony Digital will be releasing a new patch this weekend to restrict things like max power and weight. As a result, the races will be evenly matched giving everyone a equal chance to win.
In an interview with Eurogamer, Yamauchi said that they had “received a lot of demands for having more regulations placed on the online play” and as a result are going to push out an update this weekend. Yamauchi also stated that the servers were getting hit pretty hard so you may experience some disconnects when playing online.