A bunch of the higher end equips use ability as their required stat. These are mostly really good all class weapons, like the Lambda Aristin, which are worth using because of their fantastic utility.
For your mag, I would say just dump the rest of its levels into S-atk. 30 is a good amount of ability/dexterity (whichever you prefer to call it) so you should be able to equip the ability weapons and armors once you cap out. To do that just feed it weapons to raise it's S-atk and then feed it monomates once its ability stat gets near leveling (since monomates raises S-atk, raises S-def, lowers ability). It'll be slow and tedious, but it'll pay off in numbers.
Also excubes are a sort of reward for grinding once you hit a level cap. Every "level" worth of EXP past the level cap you go, you get 2 excubes which you can spend in an excube shop to get various odds and ends. PB changing devices for your mag, particle effect armors, myroom tickets, armors with luckyrise on them and some other stuff too.
As far as new equips go, just remember; everything you see right now is going to be outdated and outclassed sooner or later. Keep up with new stronger weapons as you see fit.
