I can say the Ohlins will not be as soft as stock, even at the softest setting. What I can say is that the all-around ride will be much more solid. At least I can say this for my 335is. I just want back to stock shocks/springs from Ohlins. Feels like I am riding my my Ford Explorer now.
Even will all of the M parts still on.
I don't think any of the kits mentioned will give you a softer ride. Don't know anything about Eibach springs, feel they would kill some handling performance.