I can't seem to find anything concrete on positive gains to be had, however I'm not saying they don't exist. They claim to be a few pounds lighter than stock. From what I can see, they seem to be a well-sorted company that delivers a good quality product. They are obnoxiously loud and their look is definitely eccentric.
Two Bros on the other hand, has been known to have shoddy service and the quality of their products are subpar. A lot of the carbon I've seen is starting fade and clear coat starting to yellow, and a lot faster than others. I've heard that gains are fractional to those had by the reputable, quality brands (ie. Graves, Akra, LeoV, etc.). I know of two people personally that have had their canisters explode on them, packing coming out and everything.
If you want Toce, most people here will give you poop, do with your bike what you want. Now if you want Two Bros? I'd highly suggest against it, I'm biased as I'm sure some love it, but I've seen/heard enough to put me off it.