Lowering 2IS

I've got a 2009 IS350 and I'm wanting to put coilovers on it and I know my suspension needs a refresh, I'm just torn on how I should go about it. because on one hand, I could pay decent bit more and get upgraded components, but risk the ride quality of the car, as its my daily. But on the other hand, saving money isn't out of my mind and I just want the car a little lower for now. I've already chosen the coilovers, just needing help with the res of the suspension. any help is appreciated!

Here's the link for the coilovers