I just recently completed an installation on a '03 S2000. I bought the car new in '03 and have put close to 20K miles on it. I loved everything except the sound from the stock stereo.

Two years ago at Christmas, I added some Kenwood 5 1/4 coaxials in the rear and a Kenwood wOOx that I installed in the footwell of the passenger side. This definitely was an upgrade at the time but I knew I wanted more with time and money permitting.

So this year, my Christmas project entailed installing Dynamat on the the floor of the car as well as both doors. This is very labor intensive but well worth it. My daily driver is a '98 Prelude SH. Before the S was very noisy. Now, the car appears not much noisier than my Prelude. The difference from before and after is like night and day.

I changed the stock head unit to an Alpine 9857 and hooked it up with Modifry's wired DCI. I replaced the front components with Polk db6500s and powered them with an Alpine T-220 (50Wx2) amp. I installed the amp inside the spare tire well. I retained the wOOx and the Kenwood rears.

Overall, it took a lot of time and patience but the improvement and satisfaction of doing the job were worth it.

Soundwise, it will not compare with alot of the cars on this forum. But from the perspective of trying to have a clean system that doesn't intrude spacewise, I think I accomplished my goal. Now with a quiet cabin, the clarity and added power of the Alpine HU and amp make a huge difference. The wOOx does a decent job of filling in the lows and doesn't take up but probably 3" of legroom. I would highly recommend it...I think they even have a better version of it out now. The Dynamat was probably the best thing because the car is just quieter and the doors have a nice "thud" when you close them now.

I couldn't have done without all the information on this forum so thanks to those who spend time to post "how tos" and share their installation experiences.