Its the design of the TTRS and RS3 discs. Imvho its the attempts at weight saving and thickness that causes the problem.
Audi need to look at rotor design very closely, they either need to bite the bullet and throw some mass at the problem and account for it in some other part of the suspension or come up with something trick.
A stage 1 TTRS/RS3 is capable of end straight speeds of 170mph and a dash speed of 150 its a big ask for a set of road pads and mass produced discs.
The RS3 discs are different and have a bigger offset than the TTRS which compounds the problem.
The squeal problem and fix that AUDI have come up with isn't that at all its some shims that have been fitted to EVOs and DB9s for 10 years or more, they need fitting on new discs to guarantee they work though. Audi are resisting it as the cost of the recall is 300 times the cost of the components they intend to install.
Its a shame the cost of the AP stuff is what it is, fact is there's little else out there that works if anything..
plus the cost of TTRS/RS3 pads is bloody shameful £250 for those pads is well out of order, the Pagid Blues retail for less but there's little point fitting them to a stock disc as they simply have no headroom for temp
