A$277 is about US$188. The DT Adv in the USA goes for $145. Either way, that is a significant cost that is better put to use paying for fuel.
My only expense other than a little time was a new can of Plastidip, which I needed anyway for other projects.
My modded mirrors provide a stable view at reasonable speeds. Went for a 185 km/115 miles ride in the rain today (New Years Eve) and the biggest issue was foggy mirrors when the temps dropped below 50 °F/10 °C.
I had a look at doing the mirror mod but they are tough buggers to bend. Applying some heat would have helped but I decided to leave it alone in the end has the bike is only a month old, so a bit of butchery is for a later date.