I know I needed more port area.. two seperate chambers aren't nescessary tho. I really considered RE, but I got a killer price on these orions so I went with them for now. They are comparable to an RE MX series sub, but the orions actually have a little more excursion, a more powerful motor, are more efficient, and they're "rated" power handling is higher (i'm aware RE's are underrated tho). The only thing that RE has on it is a slight larger surface area 810 cm^2 vs 780 cm^2 and RE cones are easy to replace. Also, I'm not going for all out SPL.. SQ is equally important to me as well. I know a guy with two 12" orion H2's running off less power in a similar sized car and he car do hair tricks (metered at 148 dB legal) so I have do doubt I too should be able to ackomplish the same.