Well, if your putting in 144MB of RAM, OS 9.1 isn't much different then 8.6, so I wouldn't waste your money, and just install 9.1. The HD in the 3400 is IDE (or ATA, whatever you call it) and so it's the same connector as in the 5300/190, 1400, and PowerBook G3's, iBooks, and TiBooks. I suggest putting in a 10GB drive. The video card is soldered on, along with the CPU, so upgrades are moot. Unless you put in a PCMCIA video card.