Distortion is 99% of the time not the speaker's fault. It is the amplifier powering them being overdriven. That's what your deck is facing. You turn it up until the internal amp is maxed out and it just spits out distorted power beyond a certain level.
To get decent bass will depend on the speaker, but generally the bigger the deeper. 6x9's would be decent with a small amp pushing them. Don't expect anything from a 3" speaker. I would go 5.25's in the doors personally as a minimum. Powering all speakers with an amp is a GOOD idea. Deck power plain sucks. I have 100W RMS going to each side of my front speakers and love it to death, they sound amazing.
If you really want to add some bass, you need at least a sub if not 2. A single 10" in a small sealed box with a small amp would be a nice addition. If not, I would say powering the 6x9's with an amp will make them louder at all frequency ranges, and especially down low where you sound like you want it.
For low-power applications and relatively short distances, 16 or 20 awg speaker wire will do. They aren't carrying much current from a 15-30W deck (1-2 amps at most). May want to upgrade if you add an amp to like minimum 16 awg wire, maybe even 12 awg if it's a long run like from the trunk to the doors. Brand really doesn't matter at all. Wire is wire. Good luck!
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'91 LX Hatch, 17 ROH ZR6's, lowered, 3.73's, offroad H pipe, SN Cobra cat-back, ASP pullies, 14° timing, C&L 76mm MAF, 170A 3G, B&M Ripper on a T5
Best ET: 14.593 Best MPH: 95.72 (75°, 75% hum., 2200')
1991 LX Hatch 5.0L
[This message has been edited by jonnyk (edited 07-25-2001).]