That is really a bad outcome mate, sorry. :-(
I race professionally, and have been all thru this, here my quick guide, with all I thing is what you want to know:
- Tar-Ox: is an old man in a very small, family run factory in the north of Milan. No good because they do not have the development engineers nor machinary to build at high spec.
- Mintex: they come from racing motorbikes, and that is their business. They are still learning cars, just drop it.
- Brembo: is top notch. Super engineers inside, CnC - last generation machinery to produce and high attention on procurement of raw materials.
- Ferodo - only pads: surely one of the best out there, but F2500 are ok for your wife to go shopping. You want F3000 from them, Audi's are heavy.
- Pagid - only pads: Awesome, on par with Ferodo, you only want RS19/29 compounds.
- Disks - C.T.F.: a small, but very well organized company that produces the best quality-to-cost racing disks you can buy. Has all Audi's, especially good are the composite disks, with center bellhouse and fluctuating braking suface. These disks make a 20-30% difference in braking power. I have them on my S3 8P.
I will not even mention green, red stuff, ebc or diamond something. Guys, your life is in the hands of your brakes!
What you want to do, and why the most aggressive pads: On road cars I really do not think that big brake conversions are the way to go. There are many components around the brakes, in the chassis-wheel assembly, that will be put in to situations of stress they have not been studied for. What you want is surely to get the best from your size braking assembly.
Save up, then buy composite disks on standard size, slotted.
Then buy the most aggressive pads for them, as stated above, because F2500, Pagid blue's, etc., have similar spec to the original parts, but last less.
Let me know how you get on!