I installed an ACT HS1-HDSS clutch kit last week. I was really sad to hear it make a bad clutch buzz from 3500-2000 rpm, just like my 00 s2000 did. :/

I figured I'd give it a few days, and I might've been able to tolerate it top down, but whenever I had the top up, it got annoying quick. It wouldn't be there right after I started the car, but after 4-5 blocks, it got louder and louder. Especially with the top up, it sounded really bad. It's really not damaging to the car, but it sounds really bad.

Anyhow, I'd had an ACT pressure plate with an OEM disk on my 04, and that was fine, so I decided to go ahead and put the stock disk back into my car. (I only have 3000 miles on it my 08, I was putting in a clutch in anticipation of a supercharger.)

MUCH better. Finally, noise free. Sounds just like stock, with a slightly firmer pedal (it seems like the pedal was not as firm as the ACT on my 04, maybe the slight reduction in spring force is noticeable.)

So, if you are thinking about an ACT clutch, do NOT get the HS1-HDSS, just get the pressure plate and a new OEM disk. Of course I searched on the forums AFTER I installed my clutch, and then found a bunch of other people that had the clutch buzz. I figured that the ACT disk looked pretty much stock, and that I probably wouldn't lose much clamping force.

Now, I gotta either pull out the delay valve or swap in an AP1 slave cylinder.