audi a4 2.8 quattro suspension upgrade

my 2.8 quattro has 135,000 on the clock. The car seems a little soft in the corners. Was wondering what suspension anyone recommends. I'm not interested in lowering the car, just want something stiffer in the corners and still have some comfort. Would a rear arb sort it out on its own. I remember fitting one to the mkiv golf and it transformed it. Interested to hear what others have fitted. Koni,eibach?

fitted koni adjustables to 1.8T quattro, it was easy and you have the option of choosing your ride hieght.