The 3 row's disadvantage is that the 3rd row is not as effective as the the 1st 2 rows at low speeds and idle, since the air temp is higher by the time it reaches the 3rd row.
Aren't you going to have this same problem no matter how many rows you have? Even in a hypothetical 1 row core, isn't the engine side of the tube/core always going to be hotter because of the heat picked up by the air as it moves through the core?
