My wagon is great fun. If you have a kid on the way, though, mine's probably not going to be much fun. Unless your kid is like Enzo the dog.
An 05 GT wagon is pretty long in the tooth by now. It's going to need quite a bit of work to freshen up, unless it was already done. Even at that point, you're still buying a 9 year old turbo car.
An L model might be a better start, especially as most owners throw out all the old parts and replace them with "better" parts. You dont get the turbo, but you dont need it either...as you have 3 other hot rods. :-)