I don't have the tabletop rules but could someone who does give me a clue to the question in the title? Are they much stronger? Tougher? Faster? Many more wounds? What should I be doing to the variuos fan-created Necron stats I've found to accurately model a Necron lord?

Thanks

vs

This link should be helpful

As should This Link

Are they much stronger?

Yes. The difference being the Arnie Terminator Vs the Cop or the Female on power scales.

Tougher?

Again, Yep.

Faster?

Not noticiably, unless you have the Lord who's lower half is a hover tank..

Many more wounds?

Yup.

And then theres the Reserrection Orb to bring all his buddies back up again, just like the liquid terminator..

And they have access to better gear, and they have Memories of their former lives, retaining some level of individuality..

I'd reccomend those two links for a quick read

One thing you can do is turn them into an Inquisitor... there is some evidence they have infliatrated into the Imperium in this way (Xenology)