Having changed my calipers for tokico 6 pots I thought it was time to retire the discs (just under 4mm - oops!) I bought these from a company called Trade Direct - http://www.stealthproducts.co.uk/ - they cost £196 including the postage. For that you can choose between standard round, wavey, more aggressive wavey etc. You can also choose the colour of the centres. Only downside so far is that they have a 28 day delivery time. Anyway, so far so good!