before you take your old door off I'd suggest taking something to mark where the old door was hung exactly. Both on the body and on door hinge brackets. Then measure on the "new" door where the marking on the old door was then align. Should make it a bit easier when you go to re-align everything.
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"I just drank a fifth of vodka. Dare me to drive?"
Don't take life so serious. It's not like were getting out of it alive anyway.