I doubt anyone can tell you what the best absorber is as there are so many different ones on the market today.
It's all down to personal preference. I'd go for something with both height and damping adjustment. Expensive, yes, but at least you can fine - tune to your own preferences.
While you're at it, and if you haven't already done it, try fitting a strut bar and changing the rubber bushes to polyurethane ones. It'll do wonders for your handling. Well, it worked on my friend's 325i! :lol: