What company makes the best car stereo system?

"Best" is very subjective. You are going to get all different answers because people have different preferences. Not every stereo install is the same, not every car is the same, and not everyones ears are the same. So, read reviews on a place like Crutchfield.com and talk to some friends before making any purchases. Personally, I have always had good experiences with Polk Audio. Polk makes absolutely fantastic products for the price range. I have a PolkMomo system in my boat and it sounds AMAZING! I also have had great experiences with Bose, Rockford Fosgate, and Pioneer. Just because a brand is popular doesn't mean it's good. Just because everyone jumps off a bridge, doesn't mean it's the right thing to do. Do your research, read reviews, and you'll be on your way to and educated purchase in no time.

Ehh you want an answer so her it is Pioneer DEX P99RS only due to the circuit and the tek involved focal is up and coming. also Fosgate monster amp T15K. But pioneer is falling off the greatness horse and going for the fame of glamor game so I'm not on their best regards now. last kit I ordered was a full stage 4 from crutch field. amps receiver s 10' subs+ about $8,000 or so when done with the street wires ZN 9 covering all the connection points 2 audio control matrix concert series. and a tsunami hybrid 5 farad capacitor. competition between Focal utopia and pioneer premier right now. But utopia has one up on pioneer they use beryllium in their voice coils. but just two speakers with tweets and crossover cost alone about $8,000 by them selves. Utopia BE no.8 so the best standing and yet i know none online would dare say one over another for an unknown reason but premier only by their DEX P99RS is just holding the top of the line ordeal. hope this helps, at least. but what if premier radio+ utopia fronts and C117 premier stage 4 in the back with some premier subs!!!! wow that would be awesome. but that's my direction only. (not the mentioned setup, just what I like). Also for added base stability you should check into Dynaxorb .little soft squares that cancel out wave distortion.