ThinkPad Warranties

[donking!]

Can someone explain the ThinkPad warranties and pricing on them to me?

I thought IBM/Lenovo's whole thing was that all their laptops have 3-year warranties? But then I just saw if I want to build my own T43, the 3-year warranty is a $243 option. Is that a new thing?

Also, for the premade laptops, some have 1-year warranties and some have 3-year warranties, although a $243 price difference doesn't seem to be reflected in models that are otherwise equivalent or close.

Do they just usually throw the 3-year warranty in with more expensive models? But if you do the build it yourself feature you're always going to pay extra for it?

Thanks.