with a drop like that and 18" wheels, you'll rub like hell, you really don't want to go anything lower then like and inch or so all around, and even then, that's cutting it close, you'll have to be riding around on some rubber bands.

I had the H&R sport springs on my car until I just recently got coilovers, and liked them quite a bit, they looked sweet, rode well, and weren't too low. The drop on them waa like 1.3 in the front and like 1.5 in the rear, I'm pretty sure. I had 18's on my car for like an hour, and after scraping all the tar inside my wheel wells off, I took them off, and gave them to a friend, thankfully who gave me basically what I paid for them.

With any drop greater then like 3/4 of an inch, you'll need to run on like 205/35/18 or 215/30/18, this way you don't scrape, the tires on mine that were scraping were 215/35/18, or maybe they were 225, but it wasn't that bad, I was just afraid I'd get a blow out or something If I rubbed too much.

Good luck,
Aj