Can someone who has stock shocks on a 2001 A6 Avant tell me exact part name and number I would need if I'm going to replace the rear shocks with exact original equipment?

My ride's been a little floaty/mushy and it feels like it's mostly in the back end. I would consider an upgrade, but I do not want a harsh ride, so I was going to stick with OE version. And I was hoping to get away with just the rear set replacement. Any advice would be appreciated. Thanks!