It’s a bad idea IMO. Adding 2lbs in weight to a five (Orange Five I presume? Could be a Five Spot, but either way I think it’s still a bad move) will be a seriously noticeable handicap.
If you need/want extra stiffness and better tracking then look at the Fox 36 Floats as these are seriously stiff (I’ve gone to those from Rock Shox Lyriks and can feel that the 36s are stiffer) and they will only add about 300g in weight.
In all honesty though, unless you’re heavy and/or seriously caning the sh*t out of the Five, then I can’t see you’d notice the benefit of a heavier fork over the 32. The 32 is a seriously good fork and probably has far better damping than the forks you’re looking at (though the RC3 Ti 55 is supposed to have excellent damping. Only problem with that fork is that there is only one spring available and if you’re heavy you need to use the air pre-load to compensate, which is supposed to ruin their plushness).