Don't get Sportlines if you are concerned about strut longevity. The are quite frankly, the worst springs you could get. Look to the Japanese brands (Tein, RS*R, Tanabe, Espelir) for springs and you'll be fine. If you want to properly 'slam' your car-- coilovers are the only way to do it safely. Keep in mind that when you lower the car more than 1.5-1.8'' your camber will then be out of spec, I recommend upgrading other parts of the suspension to compensate (adj. t/c rods, toe rods, ruca's, etc). And for the love of god, don't get anything else but AGX's or Koni Yellows to pair your springs with.
We have a suspension FAQ, please use it:
zerothread/11638
I wonder if my comments about Sportlines come up on searches... I should get a custom title under my screename: 'Sportlines suck--quit askin!'