You can put up to a 120GB HDD (Reasonable if you don't want to absolutely hit the 128GB limit) without going over, but it would be nice. Or put a SCSI card and a few SCSI drives in it and make it run super fast.
Or put an ATA card like the Acard AEC-6880M in it, thus avoiding the HDD size limit and gaining the capability to have a RAID that is bootable/usable in either OS 9 (and earlier) or X.
Sawtooths don't have gigabit Ethernet, so if your run Gig Enet you might want to get a PCI ethernet card. I recommend a Realtek 8169 chipset. they have drivers for 10.3 and you can use that (I use it on mine). They may have OS 9 drives.
Realtek published OS9 drivers. They were on their website. I haven't checked back in a long time. One of Amazon's sellers has a Realtek 8169 card for less than $8 shipped.
http://amzn.com/B004FLSHSW
I have not ordered nor tested one.
