Hello,
I recently bought a 2006 S model. As you all know it comes with the Standard Stock Stereo. Any suggestions for improvment without pulling it out and putting in an aftermarket one.
Would a speaker upgrade help with anything? Thanks for any input.

There is no way to improve the stock nissan head unit, the speakers themselves are great. I purchased a nissan mounting kit and a new Alpine 9515 and installed them in my 06 X.

Thanks for the info, Couldn't find what a 9515 looks like, do you have a link to one?

Just added to 10" mtx subs to the factory unit and factory speakers. Sounds 100% better.

Now, when you added those subs, where there any other special cables you needed?
Thanks.

I'm very sorry, I typed it in wrong. It's the Alpine cda-9815, there's a few of them on ebay right now, I just checked. I bought a slightly used one off ebay for my X and liked it so much I bought a second one "new" off ebay, put the new one in my X and the used one in my mustang. It's an excellent radio, and has a rich deep base with the stock speakers. But considering that I only listen to 70's music, I don't know how it would sound with more modern music. I have my entire cd collection on hard drive now, and burn them 150 to a disk in the wma format. The 9815 shows both the artist and the song title.

Now, when you added those subs, where there any other special cables you needed?
Thanks.

Yes. You either have to buy an inline converter, or use a crossover that has speaker level imputs.