Thanks for the info, the film is already shot and I am already back in the states so shooting a different type of film is out of the question for now. I've seen examples of Portra 400 pushed to 1600 with great results (search Google). Understandably "great results" is subjective but I am simply asking wether or not it would be wise to have the lab perform a push process.
Pushing/pulling is just an exposure thing since a pushed film will simply be underexposed by X stops. I slightly overexposed my photos to combat this so I was wondering what I should have the lab do.
FWIW I do all my own 120 film and my 400 speed Ilford XP2 Super looks great at 1600 with no adjustment to development times. I have never shot Portra before so I was curious as to what would work best.