I used to have a CD-32 and the upgrade I bought with it was an SX-1 expansion modual. It turned the CD-32 into vitually an A-1200 as well.
The SX-1 allowed you to plug in a keyboard, an extenal flopply drive, had a parallel for a printer and various other connections that were standard on an A-1200 (like a port for a monitor I think).
It looked like a square box that stuck out quite far out of the back right hand side of the CD-32
Yeah it was very good, wish I'd never sold it now looking back
(ps. if anyone has a version of Diggers that'll run in WinUAE or something for the PC could you send it to firstname.lastname@example.org