Hey OP. I had a similar experience back in 13' with my 6R80 car. Went from 3.15's to 3.73's. Needless to say, the 3.15's went back in and haven't come back out.
And I'll add that I had the privilege of having my stroked windsor fox in MM&FF, 5.0 Mustang, Ford Builder and Race Pages. My current car got into MM&FF shortly before it got the axe
If you're going for handling, I would recommend Maximum Motorsports Road and Track springs and Bilstein HD shocks/struts. I can't speak w/first hand experience on the a arms or ball joints, but I have the parts I mentioned on my car and they rock.
In previous times w/my car, I drag raced and...