A500, which ROM 1.3 or 2.0x?

[Cyberus]

When I had my  first A500 (KS1.3)
I don't remember any game needing 2.x to work, just needing 1MB RAM (apart from AGA games). So if I were you I'd keep it as it is.
The extra memory might be needed by some games, and will make copying disks etc a lot easier, and you can usually disable it with a switch.

So I'd probably leave it as it is :-)

edit: redrum beat me to it :-)

[Cyberus]

@Cyberus
Is it hard to install this switch that can disable the extra ram? Any links?

Well some RAM expansions have the switch, some don't. To be honest, I don't ever remember needing to turn the RAM expansion off....
It might be possible to install a switch on a RAM expansion that doesn't have one, but I don't think it'd be worth the hassle.