I bet you guys have not seen this yet. I know the 800bhp S3 is fast but that's a 3.2 lump, so slightly cheating.
Here is an s3 with bigger turbo, doesn't look extremely fast but I think we don't have any s3 with sort of power in the UK. I would like to be proven wrong otherwise.
YouTube - AUDI S3 (8L) 600ps XL MAGAZINE