Hi my Mazda 3 2006 2.3L hatchback threw a rod bearing. I am considering swapping in a Mazda 3 2007 2.3L engine and i was wondering if the're 100% compatible?

 

Your better bet would be to put in the Ford Duratec 2.5 liter engine. The Duratec and the Mazda MZR engines are virtually identical except the Ford motor has more power, gets about the same fuel economy, lasts a L-O-T longer, and best of all, is very cheap in junk yards due to the fact so many were made.