@jiffydos
I think KickFlash can store KS3.1 (or even KS3.1 + OS3.9 ROM patches if you have a 68020 cpu or greater) and it DOES work if you have KS2.04 ROMS. It was designed to host KS for OS4.0 hence it's name.
KickFlash DOES have a clock port and so can be used in conjunction with a USB Subway adapter. However again you need a 68020 or greater CPU to run the USB stack.
If you have an A2000 or A3000 (and I think you have) I personally think there are MUCH better things to spend your money on than either Kickflash or Subway but that's just me

If you have an A3000 make sure that you dont REALLY have KS1.4 and not 2.04