Unless that car was some frankenstein someone pieced together with oddball junkyard parts, there is an LSD in it already. For the apparent year of that car, all 8.8 differentials behind the 5.0 came with a factory traction lock diff (clutch style). More than likely, its just worn out. For about $50 you can rebuild the diff and reorder the clutch plate stack to fit another cltuch plate on each side (4 vs 3 per side), and add in an F-150 "s" spring for more preload. I did this for a while and it worked great but then switched to a T2R when I did the 31 spline conversion (and after I got tired of rebuilding the stock unit). The T2R is a nice improvement over the factory upgraded LSD, but for the $$$ of the T2R, it wasn't as worthwhile as other improvements I could have had for the same money.
I personally don't like the front end mods you are proposing, but it's your car so who cares what I think. I kept my front end mods simple, opened and smoothed a cobra front grill insert, spread the front fenders, CF hood. It's no full kit 240 but it doesn't look
that bad... I hope.
