RE: tow hook install
No, you don't have to take the bumper off.
You can do one side at a time and this will allow you to align the bumper easier since one side will still be tight and aligned.
You will, however, have to loosen the bolts holdling the intercooler and raise it about 3 inches to provide clearance for installing the extra brackets and tightening the hardware. You don't have to remove any of the intake tubes as there is plenty of flex to move the intercooler. The aircondition coil will move with the intercooler and those lines have plenty of flex as well.
I've installed three sets of factory tow rings on 3rd gen 2500 CTD's and they were all Sport models that did not come with them from the factory.