While I haven't had my 300 running and driving yet (zero miles/hours on it at this moment) all the evidence I have read and seen says to me that I don't need to spend time futzing with it. The amount of extra "power" coming from these well worn tweaks seems to be in the 10-15 hp range. While that may be significant for a small 4 banger diesel, it's not enough to get me going down the "tuner" path.
I'm pretty sure that the good folks at Rover spent plenty of time working on the performance curve vs longevity vs economy and decided that the setup it comes with delivers good on all three.
When I can get 550hp out of my powerstroke with a chip and new injectors, that's what I'm talking about!