I had sportlines and they sagged and did not feel firm like my h&r springs. . The h&r springs feel tight on turns and they gave me a better look on my car. I would go H&R Springs.
I'm going with H&R Sports (1.6" Front 1.5" Rear) and Bilstein Shocks and Struts. Maximum Motorsports is the people you need to talk to, I talked to em for about 20 minutes when I was having the same dilemma as you and they straightened me out pretty good. They sell both Eibach and H&R so I don't see where there would be any doubt in what they say. I'm getting the Starter Box which is the H&R Springs, Bilstein Shocks/Struts, Maximum Motorsports 4 Bolt Caster/Camber Plates, Spring Isolators and Pinion Snubbers. But like I said, you need to call Maximum Motorsports, they will tell you everything you need to know.
the consensus after researching the H&R springs is that... they are superior to most springs including eibachs...and when paired with bilsteins no ride is better...
I would go with that setup but i have free Mach1 struts/shocks ... and i still cant decide if i should go with the H&R SuperSports or the Eibach Pro Kit... the drop on the H&R's are more of what im looking for but im looking for a nice ride.. nothing too stiff or harsh...any recommendations?
I've had a set of Spotlines in the garage for about a month and finnaly installed them on Sat., Took me about an hour and fourty five min. The only other springs that I've had were on a 92 Z , and they blew major goat @$$. I have no complaints on the sportlines yet. I think that they have a more aggresive drop than H&R.