I have had like 10 Saab 900 Turbos, and I've worked on them for 100s and 100s of hours. Those intercoolers are not very good, but they sure aren't that bad! They all have the divider AFAIK. Of course, Saab OE parts like all OE parts, have been designed from a cost point of view, but compared to most other manufacturers, Saab parts are really well thought of.
That's why Saab engines are also some of the very best when you want to build a high-hp gas turbo engine.