Ported enclosure question

[mwoehr 1]

Hello everyone, I have a question regarding ported enclosures. I currenly have 2 Dcon 12s in a ported enclosure, 1.75 cubes per sub tuned to 33hz. The box was made by a local shop and fits my trunk like a glove. The guy at the shop measured my trunk and that's what fit. The dcons pound for a pair of 12s being powered by only 500 watts. I'd really like to upgrade my output by getting an Icon or Xcon 15, but height size it wouldn't fit which poses my question, how would an up firing subwoofer enclosure sound in a trunk compared to the sub facing the rear? I'm pretty confident an up firing box wound fit my trunk. How would an Xcon sound in 3.75 cubes ported to about 33hz?

Edited May 14, 2011 by Jysoe