Will an s3 milltek system for my 1.8t ARY?

The shape will be the same (i.e. the layout of the silencers), but not sure if the bore is the same.
 
take it to you local exhaust fitter and get em to put the tea and bickys down ant tell u if it will fit :D cant see it shud be any diffrent tho
 
there is a way though mate, im fitting a 2nd hand standard s3 exhaust to mine on monday as it was a hell of a lot cheaper than a new standard a3 quattro one (although tipically i found one 2nd hand on ebay tonight after iv already got all the bits), iv just had a reducer pipe made to up the bore from the a3 quattro cat to the s3 bore exhaust. then i plan to either have a custom downpipe and de-cat made or get an s3 decat and have a custom downpipe made that fits a ko3s and has s3 flanges on the cat end. this will get it flowing nice.

also you will have to replace one of the rear hangers to an s3 one as they are the other way round for some reason but i forget the part number will find it for u though, and also cut the heat shield above the silincer, and bumper to allow the tail pipes to come through