Fastest way to get to level 200 is to go solo in hard mode while using peri. This will increase your exp gained per kill by 4X. Secret augments can be obtained when you purify BBI Novelties. That's the only way I know of to get them and, like all BBI items, you might have to purify a bunch of the cursed fobs before you get one.

Okay soo. guess i hv to go bbi and kill mops there. some localition i nspecific? like im strider and i can wipe out almost everything.(lvl 153 i think im rn)

Go rob the chained gore cyclops in the upper level of BBI. I get a lot of the novelty cursed items by stealing from it using master thief. You can repeatedly steal from it by leaving the chamber and re-entering it.

Secret augments are mostly nice to have, or more: funny to have. There may be one or two, which are realy useful. But they're rng-ralated. The others are more funny abilities and qol-improvement for very rare curcumstances. (like faster shooting with a balista...)

That said, the curiousity might definitly be worth it. Sadly, your max augment stay at six. This is another reason, why I don't realy use the secret ones...