Just wanted to weigh in on the issue of ruggedness of aluminum vs copper/brass. Although aluminum is much lighter, it actually can absorb more shock than a copper brass radiator. ie; it can flex more. Any crack that happens in a radiator because of being shocked by something like a pothole or similar would indicate that the radiator already had a weak spot from a poor weld or construction issue. Good example.... We sponsor a 9 second Pontiac Trans Am race car. The driver did a full on the bumper wheel stand, panic'd, didn't ride it out and slammed the front end quite abruptly. Pieces of the car were all over the track. The entire front end was damaged, fenders, hood, suspension parts etc. However the Cold Case Radiator was bolted directly to the radiator support and was undamaged and is still in his rebuilt car. That being said, adding some type of insulation to lessen shock is not a bad precaution.
Also, that is not to say that the GlenRay rebuild or even keeping the original 3 row radiator wouldn't be good choices for many owners. It's all a matter of the situation.