I don't run the sportlines specifically, but I am lowered about an inch all around with a Roush kit. Having a set of 15x8 Racestars with control arms and the lower control arm brakets in the back with MT ET Streets made a big difference for me. Still running 19" wheels up front. I did control arms and tires at the same time, so I'm not sure which helped the most. A 15x10 won't fit without modifying the sway bar bracket (cutting and welding). Are you auto or manual and which gears are they? I know a 275/60-15 28" drag radial will fit a 1" drop, not sure bout 1.5-2" drops. A 275/50-15 26" drag radial should fit since it's 1" smaller than stock. I have a 26" on mine and it fills the wheel well less than the stock tires. At most, I would run a 17x10, but not an 18+. Drop them to about 20psi and try it out.
The springs don't allow good weight transfer, so you'll spin more. Just get a really good drag radial like Micky Thompson, Hoosier, or M&H. I realized lowered isn't ideal, but it looks nicer, it corners great, and I don't race enough to justify riding 4x4 all the time.
. I'm not the person that says it can't be done.......I'm the person who make suggestions that would be safe so yes to clear what I was trying to say..........low profile tires and drag racing don't mix.