IMO you will miss a lot if you get the 5.0 as far as drivability, fun and towing. I pass them often on the upslope. Be sure to drive both of them around a good bit. You will feel a difference.
I also think 38k is too much for that Lariat unless it has every option possible including max tow(not just the advertising "tow package" wording). My local dealership has about 10 2013's still sitting there brand new along with the 2014's. There are people holding out for the 2015 aluminum body for the weight reduction. Also, remember to check the payload sticker on the drivers door frame. The more options you add the less payload available. If you want that truck, I would work towards 5k or more off the price. Compare the real purchase price of a new 2013 and 2014 to that. Huge incentives for those.
Here are two sites to run the VIN by:
FordEtis home page
Then click "Vehicle" and then "Vehicle Lookup". Enter the VIN and expand the "Minor Features" arrow. It will say "With Load Leveling Trailer Towing"
if it really has the max tow package. The regular towing package (AKA 535)will be listed as "With Heavy Duty Trailer Towing". NOT THE SAME THING, but many dealers and even owners try to pass it off as the same thing.
The window sticker site is: http://www.inventory.ford.com/servic...icker.pdf?vin=
[insert VIN here]
Just replace your VIN instead of the bracketed words and paste that in the browser. You will see the original window sticker. Note: Does not work on older vehicles.
Hope this helps you in your decision. Happy trucking!