You can get longer Teraflex front bump stops. Jeepin By Al sells them.
http://jeepinbyal.com/liberty-2008-2012-kk/teraflex-bump-stop.html Installation is simply popping the old ones out with a pry bar and popping the new ones in (some grease or motor oil will help them slide in better).
You can get rear bump stops as well from JBA, or use hockey pucks. In either case, you'd need to remove the rear spring, drill the spring perch, reinstall the spring with the bump stop inside it, and bolt the bump stop down through your newly drilled hole.
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AtTheHelm Front Recovery System & Roof RackM116A3 Trailer build thread: viewtopic.php?f=72&t=77997