no the 831 has different valving to cope with larger impacts but i think it's a tad heavier (thicker stanchions or something)
the 831 i a remade version of the float but for Dirt jumping. it has a diffrent fit cartridge in it designed to take the bigger impacts. but the float is still just as good in my opinion. I was going to get the 32 but i havedecided to go for the 36. it may be a pound heavyer but reality is its still a light fork and it is VERY stiff.