More info required really chap, what are you using the car for, what requirements do you need, what level of cage do you need?
As Jardo said above, the more you put into things, the more you get out.
To my knowledge, I'm the only person on the forum to have caged an A3 / S3 in any meaningful way, so you're unlikely to find much help, there are of course tuners on here who would be more than capable, but without doing the basic ground work first, you'll struggle to get anywhere. It's a fairly specialist area that most on here will be unfamiliar with.