For maximum output, ported would be the way to go. But for "sound", I'm not so sure. I've personally never heard an IB, but the people who have them say it's the ultimate sound. There must be something to it. It would be nice to find someone who has had both and can say from first hand experience what an IB sounds like compared to a ported.And the group delay follow the excursion curve pretty closely, so no real benefit, really.