9 inch dilema in fox body

the 8.8 would be the easyist, as long as its the stock width. that being said the 9 inch would be alot stronger. you may not need that kinda strength.

I was curious how hard it is to narrow a 9 inch rear end? Has anyone ever done this and what kind of equipment would I need? Thanks again

Since I dont know your power level fom the motor, but you do have a 5.0 so lets say 250-300ish HP, you do not need a 9 inch. The 8.8 can be made to handle 500hp and still be some what reliable. The 9 inch is more work than its worth.

contrary to popular belief the 8.8 rear when build correctly is almost as strong as a 9"

A properly built 8.8 is just about as strong as a 9 inch.
Unless you've done fabrication before, do not attempt to narrow a 9 inch. It's not a simple procedure a novice can do, most have a useless rear end afterwards due to it not being square and level once they get done.