I had a DGmotorsport front lip before w/o lowered. I have to say it really depend on the area you live in. I used to live down in LA, I really didn't have problem at all, maybe scratch it once in a while going on-ramp into gas station or shopping plaza. Else, most of the time I'd be driving on the highway which is PERFECTLY FINE, you won't have any problem if you drive on the freeway 80% of the times. However, after I went to college, I moved my car up to San Francisco, which has a lot of steep hills, bumps, dips, etc..I was hurting the lip bad, and my car (fiberglass scratch ur bumper paint). Thus, I decide to sell it and thinking of buying the urethane one see if it's better.
In your case, with highspeed sharp turn, I don't think you'll have any problem at all w/o lowered, but your drive-way may be a problem if it's steep. Additionally, since you're sharing the car with your mom, I can almost gurantee you that your mom will forget about the lip from time to time and go fast in a dip or something..then..
Anyway, hope this helps, if you need addtional opinions, PM me.