I can import it, but when I go to explode it to clean it up, etc, it crashes. Completely crashes. not a “not responding” deal. I know the design is complicated, but it seems to me that it should be able to explode it. Or, is there another way to be able to edit this design and get some faces on it to push/pull it, etc? I also tried exporting it as a .dwg, then uploading and exploding. Same thing happened.
In the first gif you can see raw geometry, the group being exploded.
But you don’t have to explode it, you can just double-click it or right-click > Edit Group, and work inside it.