assuming you have the correct tire size on your 16" wheels you should be able to lower it at least 2.5" before rubbing becomes an issue..... that should be enough to start tucking tires a little if thats the road you want to go down...
i recommend some springs that lower your car somewhere between 1.5" and 2.0". more than that and you will sacrifice ride and handling. you will need to spend around $500 to lower your car the correct way. you will want to pick up some springs and a set of shocks, preferably adjustables like KYB AGXs. as far as springs, H&R sports and Neuspeed sports are definitely favorites for ride and handling.
eibach pro kits dont lower your car much.... you will still have a decent fender gap, although the ride and handling will be nice. i have had them before and i liked them except for the fender gap.