The muffler height and width info you posted look OK but how long are they? What are the pipe offsets, i.e. center/center, center/offset, on those mufflers?
What year is your car? It would help if you updated your profile to add the year and model of your car so others can assist with your questions.
It may be a 2.25" inlet/outlet, offset/offset muffler. Case length of mufflers available varies from 13" to 19.75" which is a function of sound. All lengths should fit with the shorter ones needed a bit of pipe to make up the difference in length compared to the stock muffler.
The specs on individual mufflers are linked to that page you posted. Looks like, from that page, they list quite a few Borla mufflers.
I'd recommend you start at the Borla website, find the 2.25" pipe size mufflers with an offset inlet and outlet. You'll probably find a few mufflers with those specifications and the difference will be the overall length. Make note of those numbers and go back to the page you linked and search for them there. Then you can pick the one you want.
The overall length is more a function of how loud the muffler will be rather than fitting a specific space. I believe the stock muffler is close to 20 - 22 inches. You should have room to fit almost all the mufflers with a 2.25" offset inlet and offset outlet listed at Borla's website.