Snowfa Garage and Motorsports · Genuine BMW Parts Genuine BMW "High Power" Spark Plugs — Set of 6
12122455258 The factory iridium plug for the B58 turbocharged straight-six — M240i to X7, Z4 to GR Supra. Six plugs, one box, the whole engine. What you're buying Part Six genuine BMW spark plugs — a complete engine set, new in BMW packaging Part number 12122455258 (also written 12-12-2-455-258) — supersedes 12120046646 Spec BMW's "High Power" iridium plug — the factory spec for the turbocharged straight-six, pre-gapped and ready to fit Fits Every B58 3.0L straight-six — 40i-badge BMWs and the Toyota GR Supra 3.0 Origin Made in France for BMW Know your part numbers 12120046646 → 12122455258 BMW replaced the original number 12120046646 with 12122455258 — same plug, current production number, which is why the early B58 cars are covered too. Some catalogs also show 12120055028; that's this plug as well. Driving a GR Supra? Toyota's part number 90118-WA461 is this exact plug — the Supra's 3.0 is a BMW engine, and this is what your Toyota dealer fits, without the Toyota box markup. Sold as a complete set of six — one box does the whole straight-six. Fitment — the B58 straight-six family Chassis Models Years G20 / G22 / G23 / G26 M340i · M440i — sedan, coupe, convertible, Gran Coupe, incl. xDrive 2019–2025 G42 M240i · M240i xDrive coupe 2022–2025 G14 / G15 / G16 840i coupe · convertible · Gran Coupe, incl. xDrive 2020–2025 G01 / G02 / G05 / G06 / G07 X3 M40i · X4 M40i · X5 xDrive40i · X6 xDrive40i · X7 xDrive40i 2018–2025 G29 Z4 M40i roadster 2020–2025 J29 (A90 / A91) Toyota GR Supra 3.0 — all trims 2020–2025
162 catalogued applications, including the 540i and 740i sedans — the supersession from 12120046646 folds the early B58 cars in as well. See 's compatibility table above for the full list, or message us with your VIN and we'll confirm it before you order.
Before you buy — check your engine.
- M Performance yes, full M no. M240i, M340i, M440i and the M40i SUVs are exactly what this set is for — but the real M cars (M2, M3, M4, X3 M, X4 M) run the S58 with different plugs. Don't fit these to a full M engine.
- 35i badge? Different era. A 335i, 435i, 535i or X5 35i runs the earlier N55/N54 six — those take different plugs. This set is for the 40i-era B58.
- Four-cylinder car? A 230i, 330i, 430i or X3 30i doesn't need six plugs — message us and we'll set you up with the right count.
- Not sure what you have? Message us with your VIN before ordering — we answer fast.
Fitting them — one set, one afternoon
Engine stone cold. Pull the engine cover, unplug each ignition coil connector, and lift the coils out. - Blow the plug wells out with compressed air before a single plug comes loose — grit dropping into a cylinder is the one mistake you can't undo.
- Old plugs out, new plugs threaded in by hand until seated, then torque to 23 Nm with a torque wrench — never by feel on an aluminum head.
- Coils back in until they click, connectors on, cover on. No coding, no adaptation — just a cleaner idle.
The plugs come pre-gapped — check if you like, but never lever on an iridium tip. BMW's schedule has plugs due around every 60,000 miles; halve that on a tuned car. While the coils are out, give them a look — and if you're doing a full B58 service, the genuine oil filter is 11427826799 — search our store.
Shipping & returns Ships from Eureka, California — free shipping, carefully packed, fast handling Returns 30-day free returns — we pay the return shipping Seller Top Rated Plus · 9,400+ parts sold · 99.8% positive response Snowfa Garage and Motorsports — Genuine BMW and performance parts, new inventory every week. We sell only genuine OEM parts: what's pictured is what ships. Fitment questions? Message us with your VIN — we answer fast.
