If you have a little one on the way, I would actually suggest not to get a WRX. The last thing you want is people wanting/trying to race you while you are trying to keep the little one safe. I would suggest a used small SUV so you can save yourself some money once you sell your GTI, because you will need all the money you can get once the little one pops out. With all the new expenses that you will incur, every dollar counts especially if you are paying a mortgage.
Beleive me, it sucks going from performance car to a block on 4 wheels. I did it 10 years ago when I had my first child. I went from a 1993 Camaro to a 1996 Dodge Caravan to a 2005 Hyandai Santa Fe and now to a 2011 WRX. It's like I was born again!!