I think the two floppy drives in the PC were made by TEAC. One of these was a quad density. This drive could store 720K on a low density disk. One of the two external floppy drives was a HD the other was the new 3.5". Upper right, you can just see the 20M Irwin tape drive.
At some point, I bought a 386 accelerator card for the this computer. I think it plugged into the 286 socket and took one card slot. There was an article in one of the trade mags back then that had the design for one.