My Capri is lowered and I don't go over speed bumps. LOL Only speed bumps in my path are at work and I just go over em with half the car or go around completely.
I would double check and make sure you got the Pro Kit....my car has then and i'm nowhere near slammed, even with low profile tires and a valance on the front of my car. Sounds more like you have Sportlines.
If nothing else, it pays to go the extra mile when doing your exhaust to make sure they're as tucked up to the floor board as possible.
I even have full length headers and mine only scrape on the gnarliest bumps or really crappy parking lot entrances. Maybe your exhaust just needs raised up some.
Here's a pic from back in the day when i had cut stock springs...it ended up about as low as you'd get with the Sportline springs. If not for having full length headers i could've left it like this, but it was a REAL challenge to navigate speed bumps, and i was real worried about hitting a pothole and destroying a header pipe or something so i bought the Pro Kit and they've been on for about 2 years now.