Sway Bar and Steering Stabilizer Questions on 1999 Shasta

Here's Thread I Mentioned Above and it does NOT seem you need to drill under there. You may want to cut a couple bolts shorter, but that's easily done out-from-under.
Hellwig has tech support as noted in the thread. Check on the bar with the better ground clearance. That clearance comment also relates to the clocking of the brackets you add to the axle tubes.