94 and 01 componets

[muddyman184]

I have a 94 and i was on craigslist and seen an ad that a guy had a few 01,02,03 3.8 engines and transmissions. My question is are all the computers and harness the same or did they change through the years i am going to need a new transmission,just figured ill just get a newer engine and go through it since ill probably have to swap the trans. :: i did search that's why i posted this and wanted to make sure completely .

Thanks