Somewhere you said you are living in Australia. I think you need to find some steam friends who play the game in that corner of the world. Maybe the US would be ok but I wouldn't know for sure.

The only time I have had lag was when I was playing a guy who was in New Zealand and I am in the UK.

When I lived in East Asia and played games with my brothers back in the UK there was a very narrow selection of games we could do because of lag issue. ARPGs (if they had a sever in asia, like Singapore and even then not perfect), race games like GRID and actually I think PA did work OK. However Australia is half as far again from Europe which is where a lot of the players are.

If there was a server in Asia and people had very fast connections it might work, I dunno.

Is the game peer to peer at the moment or does it use some default Steam servers? Might be useful to know.