The non-utilitrac bed IS different, particularly how it is reinforced for torsional (twisting) "forces". You need to consider how you would intend to use the installed tracks and if the forces you applied to the sides might be excessive enough to cause the bed to distort. Of course, Nissan would probably dis-own you if you install the tracks and the bed becomes damaged. I have not yet performed this mod on my XE, but probably will once the warranty period has expired.
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utilitrack
Good Luck.