Cheap BMW 3 Series Alternator

No — the E46 (1998–2006) and E90 (2005–2013) are different generations with different engine families, mounting arrangements, and electrical architectures, so the alternators are not interchangeable. The engine code is the key detail here: even if two cars share the same badge and fuel type, different engine codes mean different alternators. Always give the breaker your exact engine code, which you'll find on your V5 or via a VIN check, to make sure you're quoted the right unit.

The E90 generation ran from 2005 to 2013 with a facelift in 2008, and for many engine codes the alternator carried across that facelift without change — but ancillary and mounting details can vary mid-production, so this is something you should confirm with the breaker against your registration rather than assume. Give the breaker your full engine code (for example N46, N52, N47, or M57 depending on your variant) so they can cross-reference accurately. Never assume a part fits based on generation alone without that check.

No — SE, M Sport, Sport, and other trim levels on the BMW 3 Series are cosmetic and equipment packages that do not change the engine or its ancillaries, so the alternator fitted depends entirely on the engine code, not the trim. An SE and an M Sport running the same engine code will use the same alternator. The only cosmetic difference you might notice when buying used is wear or surface condition, but the unit itself will be mechanically identical.

Yes, in most cases a diesel engine will have a different alternator to a petrol engine even within the same generation, because the engines themselves differ and the alternator is matched to the engine's output and mounting points. Within the E90 generation for example, a 320d with an N47 engine will need a different alternator to a 320i with an N46 or N43 engine. Always supply your engine code and fuel type when getting a quote from a breaker to make sure the right unit is pulled.

The gearbox type does not directly affect the alternator itself, as the alternator is driven by the engine rather than the transmission, so a unit from an automatic and a manual car with the same engine code should be the same part. However, if you're unsure whether your specific car has any ancillary differences, it's worth mentioning your gearbox type to the breaker when you enquire, as they can double-check against your registration. The engine code remains the most important detail to confirm first.

The E46 ran from 1998 to 2006 with a facelift around 2001, and whether an alternator crosses that facelift boundary depends on the specific engine code involved — some engine codes span the facelift unchanged while others changed. Name the boundary to the breaker and confirm against your exact engine code and registration, rather than assuming compatibility based on the generation name alone. This is the safest approach because ancillary mounting details can change mid-production in ways that aren't always well-documented publicly.