I have had several competition audio systems over the last several years and know a little on the subject. Not to contradict the other thread, but power is the most important thing. If you put a high end speaker with no power, it will not sound any better than the cheap one you replaced. You will always get better sound putting a better receiver in front of a cheap pair of speakers than a cheap receiver in front of a good pair of speakers. Jensen is right around Walmart quality, so don't expect too much. If you look at the high end speakers on the market for mobile audio (Focal, JL Audio) they all require a great deal of power. This is because the magnets and voice cones are much larger in better speakers than a cheap paper speaker. You possibly could end up getting worse sound with a better pair of speakers if the receiver is super cheap. If you have a Jensen with a separate car amp, you can replace that and it will make a HUGE difference. I would do that before you change out the speakers. There is one simple rule for audio quality, you have to pay if you want to play. A better car receiver will have a more powerful output signal, which will amplify much better than a weaker one. High end Eclipse and Alpine decks have 5V or more outputs, where I would bet the Jensen is less than a volt. It is like anything else, garbage in, garbage out. Good luck and have fun with it!