Question about SLI

I just so happen to be one of those people who doesn't have a PCI-E or AGP slot, and I was wondering: can I run two graphics cards in SLI using just PCI slots? I have plenty of those
. I have an Nvidia GeForce 6200 with 128 MB of memory. I found another one on Ebay for pretty cheap, but with 256 MB of memory and a slightly overclocked RAMDAC (whatever that means :-?).
First question: Can I put both of those in my computer and run them in SLI?
Second question: With a PCI bus's speed, would it do me any good?
Third question: Does the difference in memory matter?
Sorry to ask so many questions, but I don't exactly know what I'm doing
. Anyway, thanks in advance for the advice! 

First question: Can I put both of those in my computer and run them in SLI?
Second question: With a PCI bus's speed, would it do me any good?
Third question: Does the difference in memory matter?
Sorry to ask so many questions, but I don't exactly know what I'm doing

