Private races in My Lounge are on a Mesh network, public races in Open Lobby are also on a Mesh Network unless the "Fixed Host" option is chosen by the host in which case it's then on a Star network. It's all explained in the GT5 online manual which can be accessed in game, have a read up & hopefully that'll tell you all you need to know.
Yes they both are, 99% of console's games use p2p.
There are no gt5 REAL servers,they are just indexes not dedicated servers, mesh/star network basically mean host migration ON/OFF( if i correctly remember u cant uncheck the fixed host option in private lobbies,thats why private lobbies are on mesh network only).Conclusion:if you are the host,you will serve the data to ALL others players.
