max dimensions (for my sport) 41.5" wide, about 30" deep (depending on how close to the hatch he wants to get, i think 31" is about as far as i'd go, depending on port placement and size) and 20" or so? to the top of the back seats. around there. 15" high, 25" deep, and 41.5" wide will give him 7.34 cubes before displacement. plenty of room for sure