I was in the same boat as you a while back. I bought a set of Tein H-techs at first because I was worried about tire wear and at the time there wasn't much info in regards to lowering with RAS (Rear Active Steer) and how low you could actually go before it effected functionality. They where able to get the alignment within spec, but honestly it was not
I then researched many springs and finally decided on Eibach's Prokit. Camber is a little
out of spec, but not terribly too much. I believe spec is a little negative anyways
. Ride is very comfortable and bump-stop trimming is not necessary as I hear it is with the Sportlines. Ride quality was surprisingly similar to stock. (sport tuned)
I went with KYB GR2 struts/shocks and they seem to be holding up just fine. 11k so far.
Tokico HP's, AKA blues
are also an excellent, cost effective strut/shock for lowering springs.
I also went with Nitto INVO's as they are uni-directional so that helps a little
with wear. Wear is not bad enough for me to justify camber kits so I am also happy with that.
I think all in all my setup was around $550. A bit cheaper than coilovers, but to each is own and for my needs they weren't for me. Any lower and I wouldn't be able to make it up my driveway.
You need to ask yourself what do you plan for your car? DD, track, drift, etc... In my case I am building a fun, comfortable, street car.
Here are some pics for reference. (no spring mount mod) They did settle a tad bit more over time. I hope this helped.