Seriously from all I've researched the biggest bang for the buck on the 3 valve V10 is custom tunes. Over on
Ford Trucks there is a 6.8L V10 section and hours of reading on the huge improvement Mike's tunes provide. You have to weed through all the 2 valve posts as there's not much to gain by messing with the 3 valves intake or exhaust. Check out
this thread and watch the video.
I'm in the process of selling my 2012 6.2L so I can purchase a low miles V10 F350 in the 2008-2010 era. I will have one of Mike's tuners in my suitcase when I fly out to the location of the new truck.
Jeff