It's not that it can't be done but your options are somewhat limited You also have to take into consideration the wire harness would have to be rerouted, shortened or lengthed depending on the new location, mounting points etc...
Adding silicone around the hvac air inlet, while not the prettiest solution, is pretty effective and cheap compared to the alternatives.
Adding silicone around the hvac air inlet, while not the prettiest solution, is pretty effective and cheap compared to the alternatives.