In my every day car I have a stock 5.1 dolby pro-logic system. have found center channel speakers for autos. Does this require a special head unit? I love the sound and thought it might be cool in the s2k.
That's a good question! For a Honda S2000, or any other car with a 1DIN stereo, you will likely need something like the signal processors below to get a center channel signal. Basically you will need any aftermarket 1DIN stereo with RCA outputs, connect those to the processor and then you can run an aftermarket amp and speakers.
This is a lot of work for your specific application (not much space in a roadster!) but if you love 5.1 surround sound, it might be the only way to get it for this car.