I have a 2001 silverado ext cab. I have a alpine iva-d100 head unit and a JL audio stealth box with a 12w3V2. Im running stock speakers and want to upgrade. I have been looking at the 6.5" Ifinity KAPPAs for the fronts and the 4x6 infinity KAPPAs for the rear. Ive heard that these are pretty good speakers but shouldnt be run without an amp for they are a waste of money otherwise. My headunit has a built in amp which i believe is 4channel, 18watt RMS/ 50wat max. Would these be good for my truck and my setup or suould i be looking at something else cheaper? Any suggestions would be appreciated for i am not to knowledgable in the speaker department. Thanks