I was under the impression that the tt hubs were compatible . . . .
Jabbalad bought the TT hubs from me, I have PM'd him tonight to see how he has got on with them. Hopefully he will shed some light on the subject.
I have some TT arms to go on mine at some point but they are not compatible with the S3/Cupra hubs. I undrestand that the balljoint can go on the other side of the arm but it's not meant to and that means the knurled face will be redundant. I cant help feeling the balljoint may move if hitting a pothole etc.