You are right, most of the time. Some people break their manifolds up so that the first two cyls take one turbo and the back two take the other turbo. They can be sized smaller that way and spool quicker as a whole system than a bigger single turbo system. Still seems like a big PITA to do with a Corolla. Oh well, people say the same thing about my Explorer too.
You VERY very very rarely see a turbo system like the one I described above because that would be two itty bitty teeny tiny turbos on there!