This is an example of a big brake kit:
https://www.killerbrakes.com/product/audi-rsq3-big-brake-upgrade-brembo-8pot-calipers-365mm-wave-brake-discs-new/
S3 brakes bolt straight on as long as you get all the bits. Here's the full list:
You can install the S3 brakes on your car but you have to get all the parts, not just disks and pads. You need the calipers, the carriers and a few other bits.
Front, if you want to do it properly:
LH CALIPER 1K0615123K
RH CALIPER 1K0615124K
CARRIER 1K0615125G qty 2
RETAINING SPRING 4F0615269 qty 2
PAD SET 1K0698151B
BRAKE DISC (345x30mm) 1K0615301M qty 2
LH SHIELD 1K0615311C
RH SHIELD 1K0615312C
FLEXI HOSE 1K0611701N qty 2
BOLT N10647602 qty 4
SCREW N90948802 qty 4
SCREW N91073301 qty 6
BRACKET 1K0611841A
BRACKET 1K0611842A
SCREW N90718601 qty 2
PIPE 1K0611763A
PIPE 1K0611764A
CLIP 191611715 qty 2
And for the rear:
1K0 615 423 G caliper left BLUE POWDER COAT FINISH
1K0 615 424 G caliper right BLUE POWDER COAT FINISH
1k0 615 425 T carrier left BLUE POWDER COAT FINISH
1k0 615 426 H carrier right BLUE POWDER COAT FINISH
1K0 615 601 N rotor (2x)
5N0 615 611 E dust shield left WILL NOT FIT w/o serious modifications
5N0 615 612 E dust shield right WILL NOT FIT w/o serious modifications
1K0 698 451 K pads
N 910 815 01 bolts (4x) â rear (carrier to hub) 14mm triple square
cheers
Steve