Recently just did this.
1) Cheapest, effective way to do it is with a decent set of springs Eibach or H&R . Both will lower it enough to improve handling but with out going so low that you have issues driving around town. £160
2) Coilovers allow the ability to set the car up to a particular ride hight but to get one that gives you a decent ride as well, you need to pay decent money. The cheap kits wont do it. £800+
3) If you want the best improvement in handling over a huge height drop, go for a decent set of uprated shocks with matching springs. £500
I went for the Eibach sport line springs and the ride is just low enough to fill the arches perfectly, handling is amazing and the ride quality is almost exactly the same as OEM.
Also look at getting a SuperPro ALK fitted at the same time, I did both and it was like getting back a different car.
Low Enough for me