[M4Lou]

Same engine, S58 in M4c and X3Mx - air filter elements in X3M are significantly smaller. Trust BWM engineers. The stock M4 air filters/housings have been lauded for being pretty efficient. Maybe the M4 element/housings are way larger than needed and the X3M's are adequate.

Anyway - I just noticed it when buying BMC's.

Pic is 50% of element for each.

[M4Lou]

Made a mistake w/ that post. The large element is from the wife's M40i (was wondering why I could only find one).

The actual size of a single element for an M3/M4 is even larger (now, the pleats are more shallow - not sure if that makes for a big difference in surface area). There are two per car.

Again, really surprised at the limited surface area for the X3M elements - in comparison to M3/4. The little coal filters are tiny. I mean, same engine/S58.

Does this argue more for a larger surface area, after market filter for the X3M's ?? Idk.