The 3.58 rear end was used in the V8 LS' Until June of 1999 (2000 production line), after it was changed to a 3.31 and remained 3.31 until october of 2002 (as the 2003 production line). As for the V6, with a stick its a 3.07, with the auto its a 3.31.
As far as i know, there are no taller gears that will fit the ls/thunderbird rear. I am planning in the future to swap my 3.31 out for a new set of 3.58, but for the $370, plus install kit (crush sleeve, fluid, modyfier, ect.) and the time involved, i dont think it will be worth it. It is such a minute change i dont think i would notice a difference. It would be about the same a dropping a series (1/2inch or so) off of your stock tire size.