Congrats on the purchase! I have only sat in a new golf R and been a passenger (not driven one), but the interior is flawless (to me at least). I guess I am very similar to you in that for a DD, the golf R wins out. You have a track car, so have fun in that. To me, the golf R and STI were not THAT far apart acceleration wise (relatively speaking, the golf isn't a prius), big deal that the STI is a bit quicker, just put your foot down a bit more in the golf. Both are quick enough to get yourself in trouble on the street.
To me, being a young working professional, the golf R seems like a fantastic car for the money.
However, I do drive a modified (keeping the stock exhaust to be quiet though) 2010 Lightning Red hatch so my immature/ boy racer side is still winning out.
Nontheless, sick car! Enjoy!