I had a HDSS and a Streetlite flywheel installed by STM about 1000 miles ago, so it's still pretty fresh. Pedal pressure is slightly stiffer than stock. The engagement is significantly more direct compared to my worn out stocker, but not difficult to modulate. No lockout shifting at ~7K, but I'm not exactly blinding-fast on the stick. I'm still breaking in, too, along with the clutch.

 

it looks like a very promising clutch (i'll probably get one), but i think there are maybe 5 people on evom that are running it and have posted about it. longevlity is def unproven.

op: i might have already said it, but the factory clutch is good for 380 ft-lbs and 470 whp with no launches. i've been there for a year. at 350 ft-lbs and 400 whp, it can probably handle a few good launches. an act organic can surely handle it no prob. if you launch, expect your clutch is eventually going to chatter.

 

ACT HDSS. Rated at ~400 ft/lbs at the flywheel, so it'll handle 400 whp no problem. And it's barely different than stock in the drivability department.

 

I have driven all Evos with various clutches - ACT HDSS, 6 puck ACT, Exedy single disk, quartermaster, Exedy twindisk - and out of all of those I prefer the Exedy twin disk. The twin disc I had in my personal Evo did not chatter, held all of the power everytime I needed it, and pedal pressure was just a tab bit stiffer than stock. Yes, its more expensive, but well worth it. Spend the extra money and you won't look back.