I was looking through the Chevy Duty catalog and noticed a heater and defroster assembly (catalog #68-991A $149.95). Since my old dog lacks a heater and it could sure use a defroster on these cool, foggy winter nights at the beach, I was thinking this might be a good add on. Just wondering if anyone has had experience with this unit and how hard / easy it might be to hook up and what kind of room it takes up in the cab. Thanks!