Looking for aftermarket speakers , witch one I should go for, 4 om or 8 om? max power range? Sensitivity? Pulled out my speakers and there is no specs on them. Just the sticker "ALPINE" Made in China )).

 

Car speakers are pretty much all 4 ohm. Start there. As for power, you are going to need speakers capable of 25W RMS/50W peak at a minimum. Sensitivity is based on parameters that you can't really control. Granted, if you are stuck between 2 speakers, then let the deciding factor be the one with the higher sensitivity (sensitivity is simply a measure of how much sound the speaker produces for a given amount of power in, so a speaker with a higher senstivity will be more efficient and produce more sound for a given amount of power applied).