[buzzkillwill]

Wheel weight does make a difference, along with diameter.

The 17" OR wheels are much lighter than the steel 17's. So much so that all four (with tires) are (about) 100lbs. less than the steelies. 100lbs lighter should shave about 1/10 off your time.
Generally speaking, if you have less unspring weight to turn in the tires, you'll get down the track with a higher speed. Whether or not it's a faster time, that's really in your launch.

As for track prep, if you're running street radials, I wouldn't lower the tires, I'd leave the rears the same, and inflate the fronts, slightly. Less drag, and it will help your trap speed, slightly.

I'm pretty happy with my track times. Iv'e spent about 550 in mods so far and you can see my times in my sig.