Won't going from 17's to 18's fill in some of the space from the top of the tire to the bottom of the wheel well? While this of course wouldn't actually physically lower the car, I would think it would give the appearance of being lower, just because the top of the tire and bottom of the wheel well would be closer together.
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Go Slow or Go Fast. I really don't care. Just GO! 
Year & Model:
2005 GT 5 Spd
Dyno Numbers:
Zero. Dynosaurs are extinct.
Quarter Mile Time:
It's 25% of the time it takes me to go a full mile.
Mods:
Installed:
SLP LoudMouths
Steeda Complete C.A.I. Kit
Motive 4.10 Gears
SCT X-Cal2 Tune (By American Muscle)
Sequential Taillights
Next:
Hurst Short Throw Shift Kit
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