Road Glide Street Glide Harley Davidson Screamin' Eagle
The decision most buyers actually have to make here isn't which part looks best. It's which Stage kit matches the engine they already have, and what that pulls in behind it.
Stage kits are matched to an engine size, not a model name
On the Milwaukee-Eight alone there are separate Stage IV kits for taking a 107 up to 114 cubic inches (92500062), a 114 or 117 up to 131 (92500080), and a 107 all the way to 128 (92500077) — three boxes carrying the same name, told apart only by the engine you're starting from. The Twin Cam line has its own Stage III kit, topping out at 103 to 110 cubic inches (92500035), a different range again. The standalone Stage inserts (25600118 to 25600129) are stamped with both a stage number and a cubic-inch figure for the same reason. Buy by CI, not by Stage name alone.
Fitment traps hide in parts that look identical
The clearest case is the ignition wires. "10mm Phat Spark Plug Wires" is one product name sold in at least seven separate fitments on this shelf: a '99 to '17 Dyna needs one set (31937-99C), a '91 to '98 Dyna, '85 to '99 Softail or '80 to '84 Touring bike needs another (31964-89C), and a '09 to '16 Touring or Trike needs a third (32318-08A). None of them interchange. Order by name rather than by year and model, and you will get the wrong one.
The tune, and the extras that don't come in the box
Harley-Davidson's own UK listing for the Stage IV kit it sells here (92500146) is direct about it: the kit "Requires ECM recalibration with Screamin Eagle ® Pro Street Tuner for proper installation." The tune is not in the box. The same listing, and the Stage III kit's (92500141), carry Harley-Davidson's own warning in their words: "Harley-Davidson® motorcycles modified with some Screamin' Eagle® Performance products must not be used on public roads and, in some cases, may be restricted to closed-course competition." Ask before you fit one for the road, not after. Not everything on this shelf needs a tune on its own; a slip-on muffler is a different job to a full engine kit. Check the specific listing, or ask us, before you assume either way.
Screamin' Eagle also covers suspension and one very specific clutch. Öhlins-tuned rear shocks sit on the same shelf as the Stage kits, and they are three fitments, not one: Harley-Davidson lists 54000350 for '23-later FLHXSE and FLTRXSE and '24-later Street Glide and Road Glide baggers, 54000325 for '18 to '24 Softails, and 54000384 for '25-later Softails. The slipper clutch built for VRSC models (37938-08KA) fits the old liquid-cooled V-Rod line, discontinued in 2017 and mechanically unlike anything else here. The Street Cannon slip-on mufflers split two ways as well: 64900555A and 64900554B are listed for '17 to '20 Touring bikes, 64900638 for '18 to '20 Deluxe and Heritage Classic, and all three need muffler clamps bought separately. Harley-Davidson's own UK listings mark each of them "ECE Certified" and "Designed for International markets that require ECE certified mufflers". That is their wording, not a promise about your MOT. The DVSA's MOT test carries no decibel figure: it fails an exhaust judged unreasonably louder than a standard system, checked warm at around half maximum revs. Ask before you fit one, not after your first MOT.
Whether a particular kit affects your warranty is also worth raising with us before you order, not after. These are genuine Harley-Davidson Screamin' Eagle parts, for sale with 10% off RRP and free UK delivery available, and the parts desk can talk you through fitment before you buy. For anything Screamin' Eagle doesn't cover, the rest of our Harley-Davidson parts range is next door.