They present this quite nicely in the brochures- which you can view PDFs of on the Audi website.
Here you go - pages 16 and 17.
At a quick glance of S Line over Sport its;
- S Line sport suspension
- Black headlining
- Nicer inlays
- Perforated leather gearstick
- Perforated leather steering wheel
- Milano leather sport seats as standard
- S Line door trim
- Sportier bumper, rear diffuser, side skirts
- LED rear lights
- Xenon headlights with LED DRLs
- Optional silver stitching on upholstery
- And ofcourse (love that they list this as a feature :P) S Line badges
As far as I remember, when ordering a new car the trim upgrade is cheaper than the Xenon lamps alone, so it's a no brainer if you're going to get that anyway. The Black Edition is a less dramatic upgrade from S Line, but it really depends on the equipment you'd otherwise pay for and whether that totals as more expensive than the package.
Hope that helps!
