RMS Wattage and FT^3

[FreekDesignz]

I have (2) kicker L5 12's. EACH sub is recommended for a max of 3.25ft^3 ported at 600wrms. I'm going to use these for my home theater so I'm not worried about space. I want to put both subs in an Aperiodic Bi-Chamber (ABC) Box. I know 1200wrms would be fine for both in 6ft^3 ported but could I do both of them sharing 8ft^3 with only 300-400wrms to each sub without any problems?

Thanks in advance!