LOL, this is why I have a 335i sedan now instead of the M3 my dealer got in (and why I kept my old 325i I do long too - kids, especially 0-5, DESTROY car interiors).
I understand ditching the M for 4 door practicality, but here is what we did.
When we had one, I kept my 325i and we got the Mrs. A 325i wagon used (so kid can destroy and it is not a big deal). She really loved that car and it did everything we needed.
When the second kid came, we went to an X5, which worked great, especially on trips, plenty of room for everything you need to bring (which is more than you think, believe me).
Now that the kids are both over 5 and she is carting around their friends etc, we went to a newer X5 with the 3rd row seat option.
No mini van and we could not be happier. I get my performace fix in my 335i and when we need the transport 1/2 the neighborhood, we can do it just like everyone else, plus the X5 still "drives" like a BMW somewhat.
2013 F30 335i 6MT M-Sport - Blk Saph. / Beige Lthr / Wood Tr. - Tech Pk - VSS M-Adp. Susp. M-Perf Stainless Exhaust M-Perf. brakes