If you already have the manifold just go to the parts store and see how far off the ports are from a D-series manifold gasket. Otherwise you'll probably have to get a CA20 gasket and line it up against the D.
The 85-88 CA18 is a CA18ET (sohc).89 all the way till 91 was a CA18DET which was the 200sx in the uk and 180sx everywhere else. The UK CA18DET has a different head then the JSPEC CA. Just wante to clear some things up. I do have a spare manifold though if anyone needs it. I dont think it would fit though.