[YuDanJa]

Simply from what I've observed when it comes to car audio (not stating anything as "facts"...just my opinions)...I don't believe replacing the speakers will make things sound any better. If you get aftermarket speakers, you'll need a powerful amp(s) to power them to their full potential. Head units alone cannot channel that much power. Also, from what I've witnessed, people who hook up amps to factory head units often experience a whining noises coming from the speakers (the alternator) or a loud popping sound when power is turned off.
So, I'm still contemplating on whether or not to upgrade by putting in an amp and sub. Plus, the space in the back looks too small even to fit a 10" sub (and cover it with that...whatever its called--the thing you cover to hide inside your trunk). You won't get much "thump" without a big enclosure for the sub, and a typical ported subwoofer box looks like it would take up the whole trunk space.

Other solutions? I am currently looking into the Infiniti Basslink as an option.

 

[YuDanJa]

When it comes to simply installing car audio (amp, for example), I'd recommend DIY. It's really not as difficult as people imagine. However, if you don't want to go through that labor, I'd at least recommend knowing enough to let the shop people know where exactly you want the amplifier placed and how you want wires routed. Prepare for a debate, though. They'll make any argument they can to make their labor as easy as possible.
In my experience, "professional" car audio installation is a coin toss. I've seen people bring back a complete mess in their audio setup, and some very impressive. If I were to visit a shop, I'd ask them to show me samples of their work (looking for neatness), ask about how many holes they're going to cut into the carpet, ...and (especially) about possible side effects (the loud popping noises and/or whining noises from the alternator I mentioned in my earlier post).

 

[YuDanJa]

...any changes of more than 350 watts on this car I would strongly consider adding an additional small battery to run your ...compromising the cars electrical performance.

Of course...another big concern. Thanks for pointing that out. I had two amps (probably pumping out 500+ watts) connected to a "superior" aftermarket battery on my Jeep; got depleted in less than 3 yrs. I'm gonna have to break my addiction to loud thumping audio.

 

[YuDanJa]

Feraz, you're really tempting me! But, really, thanks for sharing all the information.

I started with adding a kicker cvt 10inch with a small amp...

I was thinking of doing this, too. I've never (personally) hooked up an amp to a factory stereo. Would you happen to have pics or information on what wires you tapped into (speaker/remote lead wires colors and location)?

 

[YuDanJa]

No problem man, its a pleasure! I would have to find some time to take pictures and show you exactly where I tapped into and took power. I love having the battery in the trunk, makes things soo much easier to properly wire!! I'll see if I have some time this week to post more pics that I'll need to take. I've posted some prelimenary ones on page 1 lol, thank god you didn't hear my system or you would be already in the works now!!!!

I (and I'm pretty sure many, many others here) would really appreciate that. Thanks for your time!