Ok this is my soon to be setup. I don't really care for bass and don't want my car any heavier so subs are a No no for me. I just want a high end set of speakers. Is this a good setup?

1) DLS GOTHIA 6.3 for the front speakers only
2) DLS CA41 2 channel amp for front speakers
3) 03 Jdm kit
4) pioneer double din

Am I missing anything else?

 

I assume you're getting all the harnesses and such required as well for the double din conversion. If you don't know which, check my shopping list in the stickies.

You'll probably need some spacers for the speakers. - http://cgi.ebay.com/Nissan-Infiniti-SPEAKER-SPACERS-350Z-G35-FX35-AND-MORE-/300303661531?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item45eb7e39db
Where do you plan on putting the 3" midrange in that set? You'll have to cut a new hole somewhere.

 

The harnesses do come with the JDM Kit right?

 

No.
A/C controls have a separate harness that's attached to them, but nothing from the JDM kit wires to the new headunit.