The Eminence Beta 15 is tuned quite differently than a Kilomax 15, needing a much larger box. The Kilomax 15 performs well in relatively small cabinets between about 3ft3 and 8ft3 but the Beta 15 needs a much larger box. The Beta 15 should be used in cabinets no smaller than 5ft3, and would work well in boxes as large as 30ft3. If your cabinet is between 5ft3 and 8ft3 or so, you can probably do the swap, although you'll most likely need to change the port.