Ok, if you are out looking for good, entry level subs that produce good bass, you've found it. I was skeptical at first when I bought these just becase I've never heard of the Belva brand before. I saw some YouTube videos and thats about it. I had this professionally installed with everything it came with except the power and ground, which is evidently aluminum instead of copper. Aluminum isn't as good as copper and also heats up and can cause serious damage if you aren't careful. You'll want thicker copper power wires so you can play it safe and enjoy your bass without choking your amp. But again, I had these installed to my 16 focus factory radio and I am very happy with it. Its in my trunk and with the seats closed it still produces ear rattling bass. It even makes my rear view mirror shake. But some people have left poor reviews and I'm betting its because they weren't smart with their installation. Just remember to make sure you have thicker copper wires that carry any current, and your gain is set properly so the subs won't destroy themselves. The amp has gotten warm, but not hot. Which having better cables should help keep it cool. But overall, this package is a steal for the price. Its clean, hits hard, and will make you happy if you play your cards right with the installation and care. I give a 4 for the durability and features only because I haven't had this for that long yet, will update if something happens. BUT SERIOUSLY, THIS IS A GOOD DEAL.