Sportlines are much lower (relatively speaking) IMHO.
I really like their drop but practically speaking, anything more than the Prokit (in my experience. YMMV) requires CC plates, bumpsteer assistance, etc.
I have the Prokit and like it quite well. If you dont have driveway inclines and stuff to go over, and will have CC plates and all that, I'd get the additional drop (it looks so good). H&R's look great too (and might be a hair less radical than the Sportlines IIRC).