I'm have no experience with SLI, so bear with me ...
I don't really understand why modded drivers are necessary.
In the SLI FAQ I found this:
"Q: Can I mix and match graphics cards from different manufacturers?
A: Using 180 or later graphics drivers, NVIDIA graphics cards from different manufacturers can be used together in an SLI configuration. For example, a GeForce XXXGT from manufacturer ABC can be matched with a GeForce XXXGT from manufacturer XYZ."
Can someone help a noob understand?
(I didn't read the whole thread)