I love my E92 - but then, no children. And I wanted the car to look more overtly a sports car (tho' people in the know sure do spot an E90 M3). Do agree w/ the above that the rear seats are still very useable in the E92.
If I were in your shoes (baby coming) the E90 for sure. Cheaper, just as quick (on some tracks the E90 > E92) and more of a Q-car.
E93 - well, there's about 10 days / year I really want one. Like today - crisp and glorious. But it gets as hot here as Adelaide - and that's more than 10 days - then I don't
If I lived in SoCal or back on the Gold Coast then an E93 would be just the ticket.
I love the drives in the Adelaide Hills: if you go E90/92 then get it w/ moonroof and drive the Hills w/ it open.
: I have 3 rules in my E92, no food, no drink but water and no dogs (have 4 - why we have a 'van)!