I have a CDA105...its great in all respects except the EQ. If those speakers you chose end up with a very uneven frequency response, as most speakers in our cars do, due to the acoustics of the interior, you will not be able to dial it out with the HU alone. I ended up having to get a Alpine Imprint processor add on for mine.

 

I also have this HU, but I do not think the imprint is needed for an S. With only two components (no rear speakrs), and the fact that it's a convertible, I don't think it's worth the investment personally.

I have two kicker components being fed ~75 RMS and a 10' kicker sub running ~ 400 RMS. It sounds great, I'm sure your system will be of similar quality.