Having been familiar with both forums extensively, I'd say they are equally immature (caraudio.com being more of the "I'm smarter, you're a retard, kill yourself" and ecoustics being more of the "duh...wtf is going on? i'm 14 and an idiot"). Neither site looks great if you're not into the "community". One thing is for sure though: there are way, way, way more intelligent people on caraudio.com than ecoustics. The ratio of intelligent to retarded works out to roughly the same, but on the right day, caraudio.com can make for some fairly formidable posting.
It's the "pinnicle" of discussion.