The Titanic is a better all around sub than the Solo Baric. The Solo Baric is is really designed for SPL applications. Low end extension just isn't the strong suit. For example a typical 12" SoloBaric install would have a mid 30's tuning, where the tuning for the Titanics are in the low 20's. Coupled with cabin gain, you get A LOT more bottom end from the Titanics than the Solo Barics. Will the Solo Barics get louder? That's a good question. I haven't seen a side by side. However, the Titanics get very loud. They're not your typical car audio subwoofer. In fact, they're not really designed for a car specifically. They have great low end extension, very good output, but with the sacrifice of a much large box volume needed.
If you do plan on going sealed later, the Titanic, again is a better solution, given you have the space to give them a lot of box volume. With cabin gain, the Titanics will still have better low end than the Solo's.
There is no reason to spend the extra $100.00 for a Solo Baric. If you were going for straight SPL, and had minimal volume to work with, then the Solo Baric would be a good choice. However, you have a lot of space to work with, thus you can build a large enough enclosure to take advantage of what the Titanic has to offer.
If you port your current box. Drill an appropriate diameter hole that lets the round PVC pipe fit snugly into it. Curve the PVC around as much as you need to get the 36" to fit inside the enclosure. Keep one end flush with the outside of the box. In other words, you should be able to run your hand over the face of the box and just feel a hole, not the edge of the PVC. Make sense? Don't know if I can explain it any simpler.
Then, MAKE SURE you set your gains appropriately. DO NOT use bass boost. In fact, don't even hook it up. Don't set it on your amp, or your head unit. That box will have those subs going full tilt. It will be LOUD, and it'll be loud UNDER 30 hz. A Solo Baric couldn't do that.
Sealed will give you a flatter response, and better overall sound quality. I still don't know what kind of music you listen to, but the Titanic is just a great solution for you. They're inexpensive, very high quality, and you can take advantage of them, because you have a trunk the size of the Atlantic Ocean.