You might want to see if this kit is offered on other sites like Amazon and do a You tube search to look for reviews from others who have purchased this same kit.
Right off the bat, don't buy it for the claimed "400 watts" . I guarantee that is an extreme case of bs.
I don't have any experience with them, but quite a lot of dealing in audio and mobile audio and am quite certain that those figures are very exaggerated.
Whether the final outcome of this system results in decent audio that's another story. I've heard some these kits and most sound very bright with no bass output, and that's a limited function of both speaker design and size.
I can tell you , that it is possible to far exceed the sound quality of these kits by putting together quality pieces. The downside is that doing this requires a little more effort, because you don't get everything in one tidy box. I guarantee ,though, the performance would far and away exceed what you get with these kits. JMHO
If interested , I sourced the parts for just such a system. The final pricing would probably come out cheaper than most of those kits.