As underpowering speakers can be harmful to them, should I install my Pioneer 6x9'* before I get the new HU?? I would assume it should be fine especially since I won't be using them much for a week or so, and if I did I wouldn't blast them. But I'm just asking since I've heard that underpowering is just as bad as overpowering (correct?) and I don't want to use the new speakers with the factory radio if it'* not good. Thanks.

underpowering is WORSE than overpowering

I say wait till the new HU is installed. That should improve quality with just the stock speakers, then get the 6x9s and you'll notice even more improvement.

i woull have to disagree. underpowering a speaker can never harm it. what does harm them is over powering them or sending the wrong freaquencies thats it

no way man. if you are underpowering a speaker it will get sloppy and not have the responsiveness or accuracy to pull the cone in and out. Probably more noticable with subs or components than 6x9s. I used to live at Audio King

put it this way...you'd be way better off to be using 2 much CLEAN power then not enough clean power. If the power isn't that clean overpowering can be horrible too. With the right setup of frequencies speakers will take clean power all day long

it might not get loud without enough power but it will never harm it. and sound quality isnt directly related to how far the speaker is moving as long as its moving within its xmax

People usually get this wrong.. the only reason underpowering a speaker is generally worse than over powering one is because you are using too small of an amp for too little power, which means you would stress the amp too much trying to power that speaker which would cause distortion. Distortion is what kills a speaker because distortion from an amp is when it puts out raw DC power, that is what kills a speaker, not too little power. On the other hand, if you have a larger amp putting out a lot more power, that power is CLEAN, which means the speaker is less likely to get damaged because it isn't getting the raw DC power. A speaker can blow from overpowering though from over excursion of playing it with too much power for too long. (too much heat generation warping the spider etc.)

You can mess your speakers up by underpowering, but not because of the actual amount of watts going to it. Its because they drive the amp to clipping because they are trying to get everyhting out of their amp. You do this by turning the gains all they way up to max and eventually the amp cant produce anymore power, sending a clipped signal. Clipped signals are bad for speakers.

I think I'll wait till I get my HU to install them. I don't want to wait any longer but I will. Don't want to ruin them.

It was described to me something like this (paraphrasing): When a speaker is underpowered the sound waves get chopped off at the top and the speakers move in bad ways. (Sorry Jason I killed that explanation )

You will be fine getting new speakers now instead of waiting becuase the stock speakers are 8 ohm in most cases, aftermarket are 4. THis means the aftermarket speakers will have less resistance. You'[ll be fine as long as you don't crank the HU to the point that you hear distortion. If you keep it at reasonable volumes you will be just fine, just don't try to get it so loud that you hear distortion.