No, the installation guy used the RCA pre-outs to ensure clean un-amplified signal to the Crossfire's amp. He said when people use speaker outs to feed an amp it not only colors the sound but shortens the life of the amp.

The Stock Crossfire head unit didn't sound anywhere as good as the JVC. The stock one had harsh highs, shallow mids and over boomy lows.

Some people have probably changed their stock amp and speakers but The stock ones with a nice head unit made all the difference to me.