1) if i wanna run SLI, do i have to use identical cards?
2) other than connecting the 2, is there anything else that needs to be done for them to run?
3) would i have to install drivers for both cards?
They have to have the same GPU, but the clock rates and brands can be different. It wil clock down to the slowest card. If you use cards that have different clock rates Ive found it always better to put the slowest card in the main PCIe slot.