There will never be a consensus on this so in reality any criticism should be aimed at the design, not the colours. That way, we can each customise our own tax disc as we see fit but it will still be recognisable. It wouldn't be overly hard to create a simple web page that allows users to upload their own background image to use and to alternate the colour of the centre yamaha logo. The latter may be slightly more difficult and initially I'd suggest limiting to a few choice colours.