Hi, this is my first post on these forums but I have been driving a blue ARX for a bit over a year & have found plenty of usefull information on here already. Anyway a few days ago I had my top radiator tank split next to the fill cap as as happened to a few other owners going by the posts I found. I ordered the following radiator from ebay a few days ago expecting it to fit with a bit of cutting etc but after dusting off the dremmel I have just bolted it in with everything fitting back on perfectly with no modifications or cutting needed. Even the fan shroud fitted straight back on. It has the built in transmission cooler like the stock radiator too.
http://www.ebay.com.au/itm/220872242160?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649
It's a Koyo radiator part number RA1305AL. The service from the ebay seller was also great with it arriving on my doorstep the day after ordering & it only cost $330 delivered. Cheers, Matt.