I did a clean hard drive install of both AmigaOS 2.1 and 3.1.
You only save a little bit less than 5KB memory with 2.1 but you will loose all bugfixes and enhancements I mentioned before.
It seems it is definately not worth the downgrade.
I'm not sure there is much enhancements for ECS Amigas, 3.x main enhancements was the support of AGA chipset.
I've never seen the point of upgrading my A600 to 3.1, it does everything fine on 2.1.
This pack is good enhancement for 2.1:
http://classicwb.abime.net/classicweb/gaae.htm
