Welcome to united Bimmer!
If you have to replace your shocks/struts I would recommend Koni's as you previously mentioned. I have them in my car and I really like them. The Koni yellows have adjustable dampening for ride comfort. I purchased the Koni sport kit which includes lowering springs as well. If your on a budget then you can purchase just the shocks as they work with the stock springs. Which is advantageous if you don't wanna lower the car. If you do wanna lower the car then the springs provide about a 1.5" drop which actually looks really good. Specially if you run 17" rims.