If you're looking to upgrade your clutch setup, the ACT Heavy Duty/Performance Street Rigid Kit (BM14-HDSD) is where it’s at. This kit features ACT's go-to heavy-duty pressure plate, known for its robust diaphragm design that cranks up the clamp load while keeping deflection to a minimum. This means you get a clutch that not only lasts longer but also performs better under pressure. Each diaphragm goes through a meticulous four-stage heat-treating process, ensuring you're getting top-notch performance every time you hit the gas.

The pressure plate itself is built with precision cover stampings that offer both rigidity and consistency—no flimsy parts here. But it’s the performance street rigid-hub discs that really shine. Made from premium organic materials with a high copper content, these discs excel at heat transfer and boast a steel-backed lining that adds to their durability. Plus, the chrome-moly hub is heat-treated for extra strength, so you know it can handle the heat of spirited driving. And don't worry about weight; these discs are designed to be the lightest street option, which means quicker shifts and a more responsive feel.

Now, let’s talk about the installation. You can find all the details you need here. Just a heads-up: this kit doesn’t come with a clutch master cylinder or a flywheel, but it does include grease and the necessary alignment tool to make your life easier. And yes, the pressure plate bolts are included, so you won’t be scrambling to find those.

Here’s what you can expect from this kit:

• Light to moderate pedal effort, making it easy to drive daily while still giving you that firm engagement when you need it.
• Longer friction life thanks to ACT’s exclusive diaphragm design, although keep in mind that the rigid build may lead to increased spline wear.
• Engineered with precision and balanced for smooth high-RPM reliability, so you can push your car without worries.
• Great for both street and race use—you really can have the best of both worlds.

As for the specs, here’s the lowdown:

• Clutch Disc Diameter: 9.4 inches (240 mm)
• Torque Capacity: 465 ft/lbs, which is a solid bump over the OE specs.
• Input Shaft Diameter: 1.375 inches with 26 input spline quantity.
• Weight: 14.8 lbs—light enough to keep your car nimble.

Just a quick note: this kit is designed to work with your OE flywheel, and it’s all about that seamless integration. If you’re driving a BMW 135i (2008-2013), 335i (2007-2015), or even a Z4 (2009-2016), this clutch kit is tailor-made for you. Get ready to experience a clutch that feels as good as it performs!