Hi, I finally got my 04 S2000, it came with a few presents as well but I can't say that I'm too happy. Has the following mods:
AEM V2 CAI
TEIN Green Coilevers (haven't checked exact model since haven't been to my shop yet)
J'S Racing header and Catback exhaust.

Now there's two thing that currently make the ride not as good as I thought it would be. The car is ridiculously bumpy, it's like the car has no suspension. We don't have anything that resembles ideal roads here so I have to soften up the shocks and maybe raise the car half an inch or so? Anyone have any tips on adjusting the suspension and tuning it?

Also, the car has a cat, and the sound inside the car w/ J'S 70MM catback is awful unless you're racing, which I will but not on the streets. I'll be getting an Invidia catback soon as I can pool the cash together. Overall the car is in great shape but the things that are bothering me I need some help particularly with the coilovers because I'm used to KYB's on all my previous cars and these are the first coilovers I've had on any of my cars.

P.S. If anyone has any reference or a link to TEIN's manual for adjusting the stiffness of the shocks would be greatly appreciated.

 

First off with the teins, pop your hood and look where the bolts for the coilovers come through your fender and in the center at the top there will be a dial that is usually labeled. One way will be to losen and the other will be to stiffen. If it isnt labeled turn it all the way one direction and drive it a little while, then turn it completly the other direction and drive it. One will be really stiff and the other will be a softer a ride. Once you get it to where you like it for DD then leave it. For the rear, I am not sure how they are in regards to location(never tooled around with a s2000). Be the process is the same. Just make sure you do all 4 corners at the same time and drive it both ways.

After you figure out which is soft and which is hard then adjust to where you like it.

As for the cat back and header, is the silencer in the muffler or is it taken out? Me personally I would keep that cat-back because of the brand. If anything try to see if you can buy the silencer replacement or option B would be to take it to a mufler shop and have them add a resonator after the cat to silence it down some.

You might get more answers if you post this in the S2000 forum.