My vehicle audio system doesn't have an aux in.

Steer me to what you think is the best option.

I'll just use a cable from my phone to this, and I'm not getting new speakers, so it doesn't need to be very nice.

Looking for decent quality, low'ish pricing, and readily available.

aftermarket head units don't mix well with factory speakers since factory speakers are usually only rated for 1/4 the power an aftermarket head unit is going to have.

If I don't pump up the jams, will that be an issue?

ya the power difference is just too much for it to last long.

http://www.sonicelectronix.com/item_73038_Pioneer-DEH-X2600UI.html for example is a good cheap head unit.

Better to over power the speakers then under power then... they will work fine... tone the bass down an treble up should sound fine...unless if you where blessed with some nice paper cones haha. I would recommend getting a set of aftermarket speakers if you have the cash though. Any questions or concerns feel free to contact me on here..
Thanks
Jon

4 1/2 years of installing car radio/ alarms/ remote starts /kills switches. Certified as well, good luck man.

why do alot of people say its better to over power than under power? thats complete bullshit.

Well in some senses it is. With more power than you need you can keep your amp or Headunit for this example turned down and still get all the clean power you need. If you underpower the speakers you will be forcing everything out of the amp or hu and alot of times distortion and other issues come with that.

This is especially true with subs imo

This post was edited by Killerme99 on Nov 7 2013 09:41am

even excessive clean power is bad. and what you just described isnt over powering... if u need 600 watts and ur amp is 1000 and u turn it down then thats not over powering.. the same can go for a 200 watt amp.. you never crank any amp full throttlle.. you adjust to no clipping and clean power.. like I say over powering is never good..

so what ur sayin if I run my 1000 watt rms sub at 400 watts rms clean power its worse than running it at 1500 watts rms clean power? I think not

This post was edited by eddsoulja on Nov 7 2013 09:53am

Neither being under powered or over powered is great from what I understand but with most cheaper amps and HU's being overrated on the output its better to go over so you have some wiggle room imo

Now im not saying put 1500rms on your 1000rms sub by any means but having 10% more power with your amp than your sub is rated at shouldn't cause a single issue

ill agree with that to a point.. but I promise you under powering will never ever hurt anything unless its a clipped unclean signal.. in which case over or under is bad if clipped and unclean..