You will be looking at the width. I believe the fox body rears (79-93) are a few inches shorter than a 94+ rear end. Also, I believe there is a slight difference in the width of a 94-98 rear and a 99-04 rear.
However, as far as I know, you can use your stock axles to correct some of this, and to also change the whole 4 lug to 5 lug problem with the previous 4 lug axles.
"I'm not driving too fast...just flying too low"
-03 SB Cobra vert- 2552 of 5082 Born 02/25/03
90 7up vert - new project-07 DSG Focus -DD