The ACT HDSS is my most recommended clutch for the Evo X.  Perfect for all power ranges, even some built setups.

Disc Diameter (in): 9.4 Disc Diameter (mm): 240 Disc Type: Street Disc Product Weight (lbs.): 17.3 Torque Capacity (ft/lbs): 510 Torque Capacity Over OE: 41%