i dont know what this garage refrigerator kit you mention consists of, but if a refrigerator is operated in a colder than normal area, and 55° is colder than normal, its possible that the unit will not cool properly. The reason is that a refrigerator is designed to remove excess heat from inside and displace it into the ambient surrounding air. It does not and cannot remove excess cold air.

Now in theory, you might not have any problems using this fridge in a 55° F setting, as that is still warmer than the normal 36-42° temps of a fridge. But that is assuming that there is little to no dipping below that 55° mark.

If the garage is the only place to put your second fridge, you might end up having to insulate and heat the garage during the colder winter months, or simply dont use it when it gets too cold outside.