ACT 2006 Subaru Impreza XT-M/Perf Street Sprung Clutch Kit
The ACT SB10-XTSS is built for the 6-speed Subaru WRX STI owner whose clutch has started to flare in third and fourth when the turbo comes on, or who has added power and knows the factory clutch is next. It pairs ACT's Xtreme pressure plate with the Performance Street sprung organic disc, so it holds far more torque than stock while still behaving like a street clutch in traffic. The listing title reads "2006 Impreza XT-M" because the M marks ACT's Monoloc version; the actual application is much wider, covered under Fitment below.
The STI 6-speed uses a pull-type release: the release bearing pulls the pressure plate diaphragm toward the transmission instead of pushing it. That makes the bearing-to-diaphragm connection the weak spot, and ACT addresses it with Monoloc, a one-piece hardened chromoly retainer that replaces the factory two-piece wedge collar and wire ring. With Monoloc locking the RB601 bearing to the SB019X plate, the release stays aligned even under high pedal loads.
ACT rates this kit at 598 ft-lb at the crank, 68 percent above the OE clutch. The 240 mm (9.4 in) disc uses organic facings with higher copper content and a steel-backed lining, plus a sprung hub to soak up driveline shock. Compared with the 6-pad race version, the full-face organic disc gives smoother take-off and is much easier to live with in a daily-driven car.
A slipping manual clutch does not set a transmission trouble code, so the diagnosis is done by feel and by a controlled load test.
Start with the hydraulics: check the clutch fluid level and color, and make sure the pedal returns fully and the slave cylinder is not leaking. Then do a high-gear load test on a safe road: in 4th or 5th at low RPM, go to full throttle and watch the tachometer. If RPM jumps faster than road speed, the disc is slipping. Our slipping diagnosis guide walks through separating a true slip from other causes, and the flare versus slip guide explains what each one feels like from the driver's seat.
ACT's application chart lists the SB10-XTSS for the 2004 through 2021 Subaru Impreza WRX STI and WRX STI with the 2.5L turbocharged EJ engine and 6-speed manual, plus the 2007 to 2009 Legacy GT spec.B. It is not for the 5-speed WRX, which uses a different clutch. Variants and special editions (Limited, Launch Edition, Type RA, S209, Series.HyperBlue and others) appear on the chart, but if your car has had a transmission swap, match the input spline and release style before ordering. Not sure? Send us the year and VIN and we will confirm. You can compare other STI clutch options in our rebuild kits and clutch section, including the lighter-pedal ACT SB10-HDSS Heavy Duty kit and the SB10-XTG6 6-pad race kit.
The flywheel is not included. Have the factory flywheel resurfaced to a clean, flat finish, or step up to an ACT XACT flywheel: ACT lists the 600235 Streetlite and the 600240 Prolite as matching options for this kit. Replace the pilot bearing with the supplied PB1004, center the disc with the AT90 tool, and tighten the pressure plate bolts gradually in a star pattern. Install the Monoloc exactly as ACT's instruction sheet shows, then bleed the clutch hydraulics with fresh brake fluid of the type marked on the reservoir cap. Expect noticeably heavier pedal effort than stock; ACT quotes 50 to 80 percent more for its Xtreme plates. Break the organic disc in with 300 to 500 miles of gentle driving before any launches.
| Brand | ACT |
| Part number | SB10-XTSS |
| Fits | ACT 2006 Subaru Impreza XT-M/Perf Street Sprung Clutch Kit |
| Vehicle fitment | Subaru Impreza Xt-M/Perf (2006) |
| Type | Clutch Kits - Single |
| Condition | New |
| Ships | Same business day (in stock), from the USA |
| Warranty | 1-year |
Yes. ACT's chart covers the WRX STI 6-speed from 2004 through 2021, including the 2015-up body. It does not fit the non-STI WRX.
It marks the Monoloc version. Monoloc is ACT's one-piece retainer that replaces the factory two-piece wedge collar and wire ring on the STI pull-type release bearing. It comes in this kit.
No. Resurface your factory flywheel or add an ACT XACT flywheel. ACT lists the 600235 Streetlite and 600240 Prolite as matching options.
ACT rates the SB10-XTSS at 598 ft-lb measured at the crank, 68 percent over the OE clutch.
Heavier than stock. ACT describes the feel as moderate to heavy and quotes 50 to 80 percent more pedal effort for Xtreme pressure plates, depending on the car.
Use fresh brake fluid of the type marked on the clutch master cylinder reservoir cap, and bleed the slave cylinder after the install so the pedal releases fully.
