There will be very minimal difference in performance if you flip the springs, the main reason people do it is to add (or decrease in some cases) wheelbase. You will have axle wrap no matter what you do most likely so I would plan to use some traction bars. It will probably affect caster though, if you are SOA on a 40 you will need to cut and turn so take your measurements, 1) with weight on the vehicle to see what your OEM caster is set at before flipping the springs, then 2) flip them, see what the caster differences are, and try to get it 4-6 degrees above what your OEM setup was for steering (arms farther from the ground) and point your pinion up towards the t-case. Then you should have a good idea of how much you need to cut and turn..
Hope it helps!