From what I've researched It seems that Bilstein is the way to go. There are different kinds though like "heavy duty" or "sport". Or if there's a different brand that you think is better, I'd like to hear you suggestions. I'm looking for a setup that's good for a dd that can give a smooth comfortable ride. Thanks in advance

 

You could alway go with the OEM S4 ones. But Bilstein is your best bet.