If i turn the volume up to 35 outa 40 on my HU and the INfintiy 6002I's sound a lil like there guna break up or somthing or is that because there isnt enough power going to them??
If they sound like they are going to break they are either distorting or they arnt secured properly. If you want the speakers louder without having a distortion problem then yes, you should use an external amplifier.