need 8 1/4 advice

the strength of the rear end isnt my concern. i read plenty about them, and am fully convinced that it will hold up no problem with the 360 i am running. i just really would like to throw some steeper gears in the car to give life to the bottom end. so my question is, do i swap gears in the 8 1/4 or do i buy the 8 3/4? and get the 4.5 axles from dr.diff.