I can't say if the PC12-Plus sounds like the box version because I haven't heard both of them. From my reading on their website years ago, they mentioned that the cylinder subs would sound like the equivalent box sub, so that's the impression that I have. I don't know if that still holds true, and there are apparently some differences between the cylinder and box Ultras. I'd recommend asking here (like you've done) and e-mailing SVS. They've always been prompt and (IMO) honest when I've asked them questions.