Don't think it would make much difference to me as most of the time I go to the city I have the trailer on tow.
When I used to live in Adelaide I did filter sometimes but not since having the ST though I have been tempted to do so but the gap between cars never seemed wide enough.
The lanes seem to be of minimum width, so the gap often looks way to narrow for our wide mirrors. The cars' mirrors all seem to be the same height as ours. The sports bikes zip through very narrow gaps, but I suspect their mirror only reflect the rider's elbows.
Some of those truck and van mirrors threaten to take your head off.
Good to see you posting again Stinky Pete. I was about to check whether you were still with us...
