The front speakers should be 6.5" and the rear should be 6x9". You will want to make sure you have the correct ohm speakers though. My 2004 impala has 2ohm speakers and my friends has 4ohm speakers. You can put 4 ohm speakers in a 2 ohm system but your sound quality will suffer greatly. Do not put 2 ohm speakers in a 4 ohm system though, that will cause bigger problems.
Yes, you can safely use a 4 ohm amp with one 8 ohm speaker, but you will not achieve full power. The 4 ohm amp is designed to supply a certain voltage into a 4 ohm speaker. Supplying that same voltage to an 8 ohm speaker will result in half the power, or -3dB. For maximum power, use a 4 ohm speaker, or two 8 ohm speakers in parallel.
From what I can tell the front door speakers are 6x9". The rear speakers are 5.25" (round). The dash speakers are 2". What's not clear is if the Infinity system is 2 ohm or 4 ohm. But installing 4 ohm speakers should not cause any damage, just less sound sue to higher impedance.
they are probably 4 ohm
in parallel No. Two 8 ohm 'speakers in parallel present a 4 ohm load.
Yes
Four 8 ohm speakers wired in parallel would give an effective 2 ohm load.
Parallel
Don't know how you have subs wired but should be 4 ohm load is what your amp will see.
Actually...The front speakers are 5 1/4" 4 Ohm speakers and the tweeters are .6" 4 ohm tweeters. Door speakers are easy to replace, but the tweeters are impossible to find the size. Rears are 10 ohm 6 x 9" Ovals. Good luck finding 10ohm though...Can't be found. I have not yet changed the back speakers, but the front speakers are 6 inch speakers. The stock speakers are 4 ohm. Im not sure about the tweeters and rear speakers. Just pull them out and look at the back.
If you connect three 4 ohm speakers in parallel, the amplifier would see a load of about 1.3 ohms. This definitely could damage the amp if you drive it too loud.
Ohms is a measurement of resistance between the amp and speakers. Most home audio is 8 ohm, if you run 4 or 6 ohm speakers you cut resistance down and get more power out of the amp. Say your stereo is 100X2 @ 8ohm, if you use 4 ohm speakers you should get 50% more power BUT the amp is working twice as hard and can burn up.