I just went to kbb.com and requested a price quote for a certified pre-owned 2009 Porsche Cayenne for my area. With the default option list the price range is shown as $52,495 to $54,575.
With that price in mind, if you ever use your F-150 as a truck, I would suggest a third option. Buy yourself a 2013 or 2014 F-150 Lariat with a 5.0 and 3.73 rear end (these are a bit rare, and with the 2015s coming out soon you should be able to get a decent price). I upgraded from a 2004 5.4 4x4 with 3.73 rear end to the 2013, so I have a feeling that I know what you are experiencing with your current vehicle. That truck option will give you the rumble of a 5.0 Mustang GT, acceleration that is probably close to a 2011+ Mustang V6, the utility of your current truck, a very nice interior, and a single vehicle for which you have to buy insurance. I drive my 2013 F-150 Lariat 4x4 in the winter and on bad weather days - it is not real quick, but it is enough to put a stupid grin on my face when I drive it. The MPG rating of the F-150 looks to be close to that of the Porsche, and you can run 87 octane gas whenever you want.
Of the two options that you suggested, the first option with the Mustang V6 is the one that I would choose. I don't use my truck as a vehicle for hauling very often, but there are definitely times when it is helpful. Working in a manufacturing facility in the U.S., buying a U.S. produced vehicle is also an important advantage of the V6 Mustang, at least to me.