does it really matter what size? If the smaller version of one is louder than the smaller version of the other wouldn't you think that it would go in proportion no matter what the size?
they are some pretty nice subs, from a look perspective a MOJO will hand the L7 its @ss, because they are some beefy subs, ive heard alot of L7s and they always sound good, ive only heard a handful of mojos
but i would think it would be pretty close in output due to the cone area advantage of the L7s
and memphis is a little less known brand if that matters to you