I personally have Koni dampers and Eibach springs
Rate them very highly!
Adjustable damping too which is cool

They're not cheap and only lower 30mm but are regarded as a very good set up.
Another very highly rated spring would be the H&R spring which lowers 40mm that I would have gone for had I not chosen Eibachs.
Depends how much money you have to play with really
