Tremec
They save the space because of no upper crossmember. In my case with the T56 Magnum, I have just an incredible amount of space on the sides of the transmission just because of making the floor flow into the ToddRon crossmember, which is sized appropriately. These are some in process pictures so it's easier to see without the paint. Its faster to get this out of the car than it was to take the A-833 in and out, even with more bolts.
If you're putting an upper crossmember in as you should, you'll run into the same type of issue. This thing to me, while better than some, is still kind of hokey.
I personally don't think other than time spent its any easier to fill the hole they cut either. Matching up to the floor where the auto on the floor shifter piece goes through and making it taper correctly so flows nicely would be pretty difficult.
This is with the automatic floor patch in place and the ToddRon Crossmember. You'll notice its about even with the inside of the crossmember
You'll see I had to slice it and hammer it flat when I made the upper part.