9.5/10.5's vs. 10/11's for E53

[Bunyan]

Hey All,

I'm a bit confused after reading thru some of these threads. I'm looking to purchase some 20" wheels, reps or OEM's for my '06 X and have seen different posts.

Am I understanding this correctly that with OEM wheels I would need to purchase 9.5/10.5's to fit correctly and 10/11's for replicas? Are the tires the same for both of them?

Also, what exactly does it mean when the wheels are offset? I've been toying with the idea of getting style 214's in either OEM or replicas. I also read that I would have to get a hubcentric ring for the hubs in order for them to fit? Is it safe to run a '07 wheel set on an E53?
How does the hubcentric rings work?

Thanks for helping out a noobie X owner.