I think rank 30 is suddenly a other game becouse of much more legendary bodies and above all, resistance draining weapons, maybe weapons with resistance draining could be added for lower ranks, so rank 30 isn't a total op rank?

I agree but they have to be weak like -4 resistance or -6 maximum drain for non level 30`s

Why dont also give them the Quadroople Machine Gun? and the Sure Shot?

I think it is not a good idea, because it is make too much differences beetwen the levels. For example, the max level difference is +/-6. And beetwen the levels the resistance modules and the kits are higher and higher. And probably the resistance drainers caused more and more damage in your resistance. So the example: the level 28 has -8, the 26 -6 the 24 -4 and 22 -2. And if the level 22 meet with the level 28 he has no chance. Because the level 28 has 9 resistance with multiresistance module the level 22 has just 7. And if the use their drainers, the level 22 has -1 resistance and the 28 has +7. Ohh, and if they use their resistance kits the difference will be higher. The solution maybe the maximum 3 or 4 level difference, or the same resistance drainer.