Re: # of Kids and STUFF
"Stuff" had nothing to do with size for us. Lifestyle and finances did play a HUGE role.
Our kids are able to do things that many don't get to do. They don't have loads of things but they do play sports, travel, we have a boat etc.
Kids don't need "stuff" but I do believe they need a stable home with solid finances. I feel it's my job to make sure they can experience a good childhood. That includes those silly extras like being able to afford books at the school book fair, hot lunch day (lunches are not provided in Canada and are a special treat which costs about $10 per kid.), playing sports etc.
As far as house and car size - I do think that matters. If you can't fit everyone in the car - how can you do things together - we go out together A LOT - for drives, for the day, to the beach etc.
That being said we've had to make some major changes for our newest on the way. I had to trade-in my car for a Yukon XL and we are moving this summer. The kids could very well end up sharing rooms in our new home and that is totally OK as long as they have enough space to be comfortable, which in our current home is becoming harder.