Quote Originally Posted by nik12937 View Post
The calender function is completely worth giving up in order to go with an aftermarket radio. Who even needs a calender in their car? Any basic phone has a calender.

Those line out converters are limited by the quality of the source, being the stock radio, and no matter how flat you tune the stock EQ, it never gives you quite as clean/flat as a signal as some would like. Don't get me wrong though, it won't sound any worse, just not quite as good as an aftermarket radio with dedicated line-outs. The Monsoon could be different since it's internals are better, but then money comes into play. It will save you a lot to avoid the Monsoon regardless of what you wind up doing.

Hell, even try some speakers alone and see how it sounds, ones with a 2-ohm resistance come to mind to get as much power as head units offer. My Infinity Kappa's kept me content running off my head unit until I had cash for an amplifier. The Infinity Reference are damn cheap for how loud they can be.

Subwoofers are another game. If you just want to be able to hear the low end and get a little more bump, then those bass tubes are a good deal and very simple to wire. If you want audiophile sound quality and/or serious bass, you really need an actual box sized and tuned to the sub.
To go along with what nik said, I couldn't wait to rip out the OEM radio. My head unit has 3 RCA 4 volt outputs. It means I don't need as high a gain setting on the amp. It also means a cleaner signal to the amp. I have Sirius XM directly in the head unit. I can control my 160 gig iPod from the head unit screen. I can Bluetooth from my smartphone to the head unit. I have hands free calling through the head unit. And, I have navigation.

As nik also said, those line converters aren't all of that for sound quality. It is, however the only real way to add an amp other than rewiring everything, if you've absolutely gotta keep it OEM. Since I no longer have a calender on the DIC, I just set the page to average economy. It helps remind me to keep off the gas pedal.

One more thing to consider, and it's the most important thing: cost. I have about $1,500 wrapped up in my system. That's all parts. I did the install myself. If you're not comfortable with taking out an interior, or doing quality basic wiring, you'll need to add for labor to install any of these goodies.

You may not want or need navigation. That'll save ya about $400. If I'd done a bit more homework, I would have gone with a head unit capable of integrating with my smartphone better and used the navigation apps in that.