I have read several reviews stating that the system in the S5 sounds significantly better than that in the 8. I have not heard the system in the 8 to make a direct comparison. As a musician for 30 years, and having done quite a bit of recording, I am very aware that the best sound system and recording equipment can be rendered near useless by a bad room. Perhaps the cabin of the S5 is more suitable for listening than that of the 8, making for a better sound. I do want to make 1 comment about the "thin sounding" sub woofer. The sub is not thin, rather accurate. People are so bass hungry these days (at least in the US) that many manufacturers make speakers that exagerate the low end response of the system. Somehow, this has been equated with a "good"system. Of course, if you listen to the original recording in the studio, this is not what the sound engineer intended for the listener to hear. It kills the definition of all other frequencies, destroying many of the subtelties in the sound that they worked so hard to preserve. And if you have ever sat at a red light next to a car blowing so much air from its subs that the car seems as if it will fall into pieces, that is not good sound. That is caused by standing waves (I won't go into detail) which are a sign of a cheap or poorly designed system. Trust me, the sound engineers for every band or movie score that you listen to, work feverishly to avoid such things from happening. American cars are notorious for installing radios that warp the bass frequencies to make people think its a good system feeding on this false notion that more bass is better. If that was the case, that stereo that you can get at the local discount electronics store for $500 must have better speakers than an $80,000 stereo pair of Meridian DSP 8000's. Sorry about the rant, but this is a touchy subject with me. Bottom line Enjoy a fabulous car stereo.