there is vibration like noise from the front center speaker. I can really differentiate whether something is vibrating or speaker is blown. Where can i find replacement speakers and how much do they run?

Defn dont buy oem speakers, go to any car audio store and they should be able to help you, dont hesitate to shop around and look especially at the internet......i dont know where you are but you can always call up the place where my bro works
Its called Hurleys Audio and they are in Northern Virginia and you can get to them at
703-790-8744
Try to speak to Z (my bro whos on vacation right now) or talk to Stewart

Where can i find replacement speakers and how much do they run?

www.crutchfield.com

I have been running Lanzar Speakers in my Caddy for going on 4 years now > The Vibe series < They sound better than anything i have heard, great mids and bass response and the highs are out of this world. check out their site at http://www.Lanzar.com

i think i will wait a little bit since the vibration noise hasn't been heard for a while. LOL I'm pretty sure it will come back at the most inconvinient times.

Lanzar is second rate, your much better off with mb quart or FOCAL! I cant say enough about FOCAl their polyglass series is incredible and isnt too expensive. You cant really buy them online is the only downfall. Their utopia series is incredibly expensive but completely beyond any other speaker on the market

Second Rate in your Opinion > You Pay alot for a name in this business, yet the various products manufacturing costs are very close in comparison. How much does a pair of Focal's Best 6x9s cost? just curious, and where are thay made? Here in the U.S. ?