Oaudio TC2+ 15": Worthy North Creek Thunder Replacement? And cabinet questions, too

I have an opportunity to pick a raw, unused 15" O-Audio subwoofer* from my cousin. It is a really nice looking subwoofer, with a beefy frame and an imposing black saucer cone. It would replace my current subwoofer, which is a North Creek Music Systems Thunder, which uses the Peerless XLS12 woofer and passive radiator. I love this subwoofer. It is taught, punchy, precise, and defined. It got even more precise when the North Creek plate amp died, because I replaced the amp with a Velodyne SMS-1 equalizer and an Outlaw Audio 2200 amp. The problem is that I moved recently, and this sub runs out of gas in my new greatroom. It can no longer keep up with my speakers, which are NHT VT4 towers powered by an NAD C370 amp, the way it did in my old smaller living room. I have searched this forum and found only a few posts on the Peerless and no posts about the O-Audio 15, though the O-Audio 12 and their amps as well as the TC Sound TC-1000 15 all seem well-liked. Before I bite, I have a few questions.

1) Will this driver satisfy me? I mean, after I set the EQ on the SMS-1 manually will this O-Audio woofer sound similar to my current subwoofer, except with one more gear, or will it sound much different? Will it integrate well with my speakers? As I wrote above, I didn't find anything about this subwoofer while searching, but I did find other O-Audio products praised. Is the 15 an ugly duckling or something that everyone avoids, and isn't even worth what I'd be paying for it (free)?

2) What's the smallest box I can use with this driver? I know it won't be as small as my current subwoofer, because the driver is bigger, but I don't want a huge eyesore, either. I assume I want a passive radiator, because that's what my current sub uses, but I've also heard that sealed subs are even tighter sounding. I played with the program my brother recommended to me, a free Excel plugin called Unibox, and I didn't really understand how to model passive radiators. He told me that he didn't know where to buy huge passive radiators, either, and that I should play with ported boxes in the software. Any thoughts?

3) Can I still use my current equalizer and amp with this subwoofer? The subwoofer is rated at 400W and my amp is rated at 200W and 300W.

Thanks,

FA

*I couldn't post a link because this post is my first here, but here are the specifications of the O-Audio 15" SVS from their website.


Nominal Impedance (Ohms) 4
Qts 0.368
Qes 0.398
Qm 4.803
Fs (Hz) 17.7
Res (Ohms) 3.1
Le at 1kHz (mH) 2.6
Effective Diameter (m) 0.330
Vas (liters) 357.2
Mms (g) 233.8
Cms (mm/N) 0.348
BL (N/A) 14.20
SPL (dBSPL @ 1W @ 1m) 88.9
Rated Power (Watts RMS) 400
Xmax (mm one-way) 18.1
Baffle Cutout Diameter (inches) 14
Mounting Depth (inches) 7.5

garciab, thanks for your message. The thing is, what I really want out of the system is for it to sound just like the Thunder, except more, and I'm not sure how to get there.

For example, when I compare passive radiator and vented (175L cabinet) in Unibox, the vented seems to have more output, but also a wiggle in the graph starting at 180Hz. If I bring my sub in at 60Hz, is that important? Do they sound similar, or is the vented box more of a boom sound and the passive radiator box more smooth and tight? Or vice-versa? The "step response" of the vented box seems more wiggly than the passive radiator, or closed. Also, Unibox gives me different results from what North Creek says about the Thunder, and what Peerless writes in their application notes on the XLS. Is Unibox accurate for passive radiators?

Closed seems to have the least output and require the woofer to move the most, but these are supposed to sound best? Is it because of the step response?

I have attached some curves below. Please let me know your thoughts.