Recommendations for my new stereo setup?

[1hawaii50]

I have a base 07 Altima 2.5S CVT with the base stereo system. I am looking to add speakers and a small (50-100W) 4 channel amp. I am looking at the Polk/MOMO MMC690 for the rear deck, and the Polk/MOMO MMC6500 components for the front doors. I am thinking that I will just unplug the dash speakers and not use them anymore, replacing them with the tweeters from the component setup. Also, I am planning to use the factory head unit for the time being, so I will be needing to use a line-out converter. The two I am looking at are the:David Navone NE-774V,Peripheral SVEN4

Other than the actual amp, and speaker wire, is there anything else that I'm forgetting? Anybody have any other suggestions as far as speaker/amp/loc recommendations?

Thanks for the input.