im dropped on intrax, rated at 1.75", but settled at about 3" and my front tires have less sidewall than the rears... my front bumper is about 2.5" off the ground...
i scrape everywhere, sometimes just drivin down the street ( due to the bouncy stock struts im still ridin on)
there is no such thing as "too" low, but w/a fiberglass kit, i wouldnt lower it too much.. my stock urethane tends to "flex" a lot better than any fiberglass aftermarket front end....