Right now I'm using an older Clarion drx9575rz. It says it has 3 4v pre-outs, but I have a feeling they're considerably weaker. I have to have the non-fader (sub pre out) volume higher (around 5/7_, as well as the bass is about +2, or 3. This in comparision to the panasonic where I had everthing set to 0. The panasonic was 5v, but that really isn't a big diff. In saying that, will the weaker pre-outs hurt my score? (even if I was to have the gain set higher to match the deck output)
Or will I have to invest in a linedriver?
Any advice would be appreciated.

The RMS line output of most decks seems to vary quite a bit. Its usually around 1/2 to 2/3 of the rated output.

If you can compensate by turning up the gain on your amp, There will probably not be a signifcant loss in SPL. If your gain is already turned up pretty high, I'd probably invest in a line driver. It can't hurt, and will likely double your current output, allowing you to turn down your amp gains. Many active x-overs and EQs will considerably boost the signal, so if you were planning on getting one anyways, it'd be worthwhile to see if it fixes your problem before you go out and buy a line driver.

With my older clarion 2v preout deck I gained .9 db with a linedriver. I'm not usre about your situation. I would try it to be sure.

X

I have been using a Clarion DRX7575Z for years and it works fine and I have never had any problems with it hurting my score at all. It has triple 4v pre outs too...

^^^ Probably really similar to mine then, thanks for the advice guys.