Wow Craig, didn't see that one coming! From an A4 to a Civic Hybrid? Sorry, man.
LOL! Just kidding - giving you a hard time.
Those hybrids are pretty neat cars.
The claimed interior noise level of the Civic at highway speeds is 66db. This seems exceptionally low, and is in the realm of what luxury cars were achieving not that long ago. This is a good thing.
The key is to be able to hear the quiet passages of music (which will need to be above 66db), and yet not distort when the dynamic part kicks in. This means good separate amplification for all speakers, as well as a quality sub.
Because of all the different materials at all different angles, the reflections and absorbtions in a car are huge. You will NEVER get a nice flat response curve. Depending on how fussy you are, you may want to add a parametric EQ and pay someone to "EQ" the car to smooth things out.
The one issue I can see is the amount of trunk space you require for trips with Roger & Mr Bear. The battery pack for the Civic's IMA is sandwiched behind the back seat. This is normally where the sub box and amp "rack" go. Both these things take up significant trunk space. Just something to consider.
Also, I know that the Accord hybrid has an Active Noise Cancellation system that is integrated into the factory stereo. This makes it nearly impossible to swap it out. Years ago, the Civics alarm system was tied into the stereo as well. I couldn't find anything on these things in the new Civic, but you may still want to ask the dealer.
Hope this helps.
