The "Infinity" systems that go into most Dodge/Chrysler vehicles are a joke. I'm pretty sure the name on the audio system helps Chrysler to sell a few more upgrades, but I can't believe that Inifinty would allow their name to be associated with a system that is so inferior to their other products. This is generally true with most associations between car makers and audio companies. The systems still generally produce only 20 Watts peak per channel, and have speakers that are manufactured to handle that much power. I'm pretty sure your new head unit will make short work of those speakers; you can replace them now; or wait the couple months it will take for that head unit to overpower them.
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Life moves pretty fast; if you don't stop and look around once in a while; you could miss it.
You must not have listened to a Caravan / Town & Country infinity system lately...it's one of the most impressive stock units I've heard in any car !
Bill, my best advice would be to install your clarion deck. It will only take about 30 min. to do. Then fire it up and take a listen. as long as the speakers are not blown or suffering from extreme use then it should sound pretty good. if its still lacking, I would consider an amp before replacing any of the speakers. If you feel that the stock speakers are not producing enough high end frequency response then I would consider replacing just the dash speakers.
Its been my experience that stock speakers typically will sound overall better compared to aftermarket one without an amp. The amp provide a great deal of power and dynamics to the system. If you don't plan on adding an amp, then unless the speakers are blown, I wouldn't replace them.
Just my 2cents.
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