Sorry I know this post is older but I took my 07 LS TB to a off road park when I first got it and the only "mod" that was even done to it was I took the front bumper cover off, it still had factory street tires as well and it did great
I've trail ridden and mildly wheeled my AWD 9-7x with TrailBlazer stick height suspension and I've never hurt the underside, or gotten it stuck. It's all about the driver. Don't overdo it. Don't be that idiot that thinks because he's got 4-low and a locker he'll never get stuck.
In the words of Woodie Guthrie, take it easy, but take it.