Radio/Speaker Recommendation for 2006 Prius

I have the base radio and speakers on a 2006 Prius. I believe the speakers are shot since I am getting poor quality when someone speaks and says "s". I have satt radio via an add on receiver I mounted on the dash. I have looked at replacement radios and speakers and would like to get a radio that would fit well, work well and look good in the dash that has satt radio built in, so I can lose the dash mount satt receiver. I also need to get decent speakers (2 in front and rear doors, 2 tiny ones on door by mirror). What do you recommend for this vehicle? Can the speakers be installed DIY? I don't feel comfortable doing the radio without help. I am not an audiophile but I have to have good music when I drive. I want to get this done soon. Any help you can give me would be great.

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