As already stated above don't go too mad with the lowering as well as tyre wear the other problem you get if the car is too low is the rear drive shafts hit the chassis rail under load and the exhaust back box hits the road, cossies squat like fuck when you boot them off the line so stick to a sensible ride height, I always advise a coilover suspension set up so it can be adjusted to how you want it/ what is acceptable
Luciano