I was under same situation when I ended up buying the 4.8. I loaded up the 4.4 and there was little price difference. What did for me was;
If I had bought 4.4 I would have added the 4.8 body kit and 20" wheels which would have turned out more expensive than a 4.8 but with a 4.4 engine and non-nappa, non-alcantara interior. With 4.8 you also get a nice sporty exhaust note. So saved myself the pain of doing the mods. Also when you sell /trade-in the 4.4 down the road the dealer does not put any value on the options/packages other than nav. You can check this on www.galves.com