I agree the bm is a better drivers car,3 series are more common than the S3 but i dont see many 330 ci's.
Interior is a very close thing,ive just picked up my 330 ci sport and the seats feel as nice the recaro S3 seats but are full electric and memory.
Although they look very different on the outside i really like both.
I was all set to buy an S3 until i borrowed my mates 330 ci to go and test drive an S3,getting out of the S3 and into the bm made my mind up the bm is the car for me.
Broomes3 next time im in blackpool i will give you a shout.Be nice to compare mine and your remapped s3,i will have a few mods by then.