What is really the differences between the 2MB and 4 MB Versions?
Any benefits with 4MB? Is it possible to later upgrade to arm with only 2MB?
For ADF games the 2MB version will do its job.
Most games only need 0.5MB Chip + 0.5MB Slow RAM.
The board will offer:
0.5MB Chip + 1.0MB Slow or
1.0MB Chip + 0.5MB Slow or
1.5MB Chip + NONE Slow
Kickstart always take 0.5MB, no matter if the file is 256KB or 512KB in size.
If you intend to use the ActionReplay (AR3.ROM), additional 0.5MB of S-RAM will be lost for AmigaOS. In this case the 4MB upgrade is a good idea.
Anyway the ARM controller is highly recommended.
Not only due to higher speed, but for better compatibility! Some games do not work with the original PIC chip.