I'd e-mail the company who said that and ask them why. I don't know how the filter mounts up, but if it uses the stock mounting points I can't see why you should not use the FIPK.
From the Review section of XOC:
Install the rubber mounting posts for the hear shield to the body of the vehicle. The heat shield will be attached to these posts later.
Is this why? Does the body lift change the location of the body in relation to the intake piping? Sorry, I'm extremely ignorant on body lifts.