When I first got my 03 4Runner I bought a Kenwood DNN990HD headunit and it honestly improved the sound of the stock speakers enough to where I was happy. But a few days ago I was bored at work and on Crutchfield's website and ended up calling one of their audio pro's and he recommended I upgrade my front speakers to the JBL GT7-6C components with JBL tweeters, and some Kenwood KFC-1665S for the back speakers. He promised I wouldn't be disappointed. He said those new JBL's are pretty slick.