I am right in saying you want to fit the front discs/pads/calipers from a 2008 model Audi S3 onto your
mk1 leon?
If so I very much doubt they will fit. Different offset/pcd on discs.
If you want to go bigger discs on a mk1 look out for some octavia vRS/anni golf/ old model S3 or TT brakes, these will bolt straight on