I recently got a SE/30 and installed a SCSI2SD which I created two separate hard drives. So I thought I would install system 6 and system 7 on each drive and just pick between them, which seems to work great. So my Mac SE now is feeling kind of redundant. It has system 6.0.8 on it and it got me thinking, would it be a good candidate for system 4 or 5? System 6 is the oldest system I have used, but I didn't know if there was any software that wouldn't run on system 6 where a system 4/5 may be useful?