I understand you can fit the same alloy part (upsidedown) to the rear, I have one in the box to do this but have neaver broken the original.
From an earlier post: Keith at glowplug (USA), (first to market with brace)
He suggests running a second (same front brace) upside down as leading brace in the rear, "we use the brace for the leading side in the rear upside down, and use longer bolts with lock nuts (traction tip: don't use any shims) Bolt length is 14 mm."
It is possible to buy a complete alloy set:
http://cgi.ebay.co.uk/KYOSHO-LAZER-Z...QQcmdZViewItem
There are differences in the hole spacing between the arm holders, to allow the wishbones to be at different angles.........not sure how this works, ours is still set at the default setup.