Ummm... In a stock A600 the 68000 CPU has only 24-bit addressing. You'd need an accelerator card to fix that.
Nope. You can, for example, add fastmem to an A600 using the PCMCIA slot. There is of course not as big a speedup as there is when adding fastmem to an A1200. Most 512kb expansions for the A500 were fastmem expansions. Fastmem is basically just any memory added outside the custom chips' address range.
