Just did 3.08 to 3.55's in a mustang GT last week and even I couldnt tell the diff,, customer wasnt to happy but,, it was a I told yah so kinda thing.
he also had a AODE so it will be the same as yours basically (minus 2 cyls LOL).. It shifted OK kinda early on part throttle and seemed to go past the rev limiter under WOT.. so expect the same.
If it were me,, with a assuming stock? engine.. I would install a 4R70W from a 96/97 thunderbird for the lower 2.8 first gear and install a set of 3.27 gears.
All the benefits of 3.73's with the gas mileage of 3.27's!