Pull the cargo panel, pull the subwoofer, and get some measurements. From there you can find out what fits. Or search for what other subs people have put in and look up their dimensions, then buy a sub similar to that.
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I think Jeff's install that I reposted for you in this thread is about the most instructive and similar to your situation as you will find on TYF. You will notice that his "before" pic that I reposted shows the same Bose Accoustimass subwoofer box that you found a photo of on eBay. Same unit. Compare his pic with yours.
Anyway, if he did it, and was happy with it, then it sounds like you will be pleased with a similar installation. The advantage you have with the short wheel base and the MTX box is that you have a ready made solution for a 10" sub, rather than an 8". All things otherwise being equal as far as quality of components and design, the larger subwoofer driver is generally capable of reproducing lower frequencies at louder volumes than a smaller subwoofer.
If I were in your shoes with your vehicle, and wanted the MTX box, I'd strongly consider getting the version with the built in amplifier... especially since your aftermarket head unit already has a dedicated subwoofer out. The built in amp would save so much headache in the installation, finding a board for the amp, carpeting the board for the amp, sizing the amp for the driver, sizing the amp for the folded seat clearance, running wires under the seat but making sure they don't get pinched, stepped on, or shorted through the seat mechanisms or by kids and their sports apparati... the list goes on.
I don't work for any audio company, and never heard of MTX prior to my research into subs, but there is no way I'd pass up the opportunity to have all those issues solved for me inside one ready made, pre tested box.