You've very similar taste in watches to myself. I got a Tag Carrera as my first rep, and have wanted a IWC Portuguese for awhile.
Personally i see the Carrera as more of a smart casual/sports watch and the Portuguese as a dress watch, which is why I could justify owning both!
It all comes down to what situations you think you'll be using this watch most, only reason I don't have a Portuguese is the dress occasions I go to at present aren't often enough to warrant a dress watch....
You'll be happy whatever you get but the Carrera is more practical and I think you'd get more ware out of it!
-G