There are two kits available for purchase, both intended for 2017 and later Touring models (none is compatible with the trikes sold by the bike builder) and both compliant with the noise and emissions standards in all U.S. states, except California.The first and most impressive upgrade kit is the 114/117ci to 131ci Stage IV that becomes “the largest Harley-Davidson bolt-on engine upgrade to any Milwaukee-Eight motor.” It features CNC-ported heads with 1 mm bigger valves, fully machined combustion chambers, and high compression pistons among others.The kit increases the engine’s power to 131 ft-lb of torque and 121 hp at the rear-wheel, when coupled with Screamin' Eagle Street Cannon mufflers.“It’s designed to run at high-end RPMs and provide a significant boost of torque from cruising speed. You’ll feel the difference as soon as you twist the throttle,” the bike builder said in a statement,The second is the 107ci to 128ci upgrade kit. It comes with the same modifications as the more potent one, including a 64 mm throttle body and intake manifold, and should bring power levels up to 126 ft-lb of torque and 121 hp, also when paired with Screamin' Eagle Street Cannon mufflers.Fitting these kits on bikes requires additional hardware to be purchased, including a high-capacity oil pump and clutch plate kit. Harley says these kits cannot be used with Screamin' EagleHigh-Flow exhaust systems with Street Cannon mufflers.Full details on the modifications these two kits bring to Touring Scremin’ Eagles can be found in the press release section below.