he's far from retarded, big low tuned boxes are where its at IMO:naughty: call me retarded if you wish.
the brahmas going in 3cubes@25Hz soon:naughty: should sound awesome. my B-15 was in 5cubes@20Hz for a few months, and it was insane. best sounding/lowest box ive ever had. awesome setup. it god extremely loud too. just because its 20Hz doesnt mean you wont have output
oh yeah, and you should be able to tune it a fair amount higher if you trim some port off, it might be difficult though seeing as the box is already put together