I am thinking of getting a used replacement engine for my 2001 tribute (it has the 3.0). In my research, it seems like the 2000-2004 engines are identical and then 2005-2006 are different. It seems like the 2005-06 engines are more plentiful and cheeper... Anyone know what the differences are? Are they interchangeable? what about the 06-09 engines?Thanks for any thoughts...