It works so well because it is made of higher quality graphite (triple weave, 0, 45, 90)than what comes in the kit. This makes it much, much stiffer without being heavier. It also doesn't have the millions of holes the stock chassis has (exaggeration, but you guys know what I mean). This is also what attributes to its stiffness.
As far as downsides go, I haven't found any!
If it is more suited to one type of condition, then that is on carpet, because of its stiffness. However, many people use them on asphalt as well and do not think the lack-of-flex hurts one bit! Your car will be more responsive with this chassis and you will be able to feel your adjustments even more than you could have before.
You can also get it in a variety of colors, black, blue, SSG, titanium (my favorite), red, and now gold, too.
Send a PM to BMI Racing if you want to order one