I can only refer to the rv tune. It does make a difference in the rv, calms the rpms shifts hold better. I do not have any exhaust intake changes but plan on a better exhaust as next upgrade.
With any tune there needs to be some upgrades such as intake and or exhaust but it all depends on what you want. In my PSD I have upgraded the exhaust but not the intake because it is capable of providing air flow up to about 450hp so no need to change. the exhaust will improve performance and make it easier to drive. I have installed Gibson exhausts on my tow vehicles cat back on the gasser, turbo back on the diesel.
It all depends on what you want, go to ford enthusiasts V10 forums and read up there for trucks and x's. Many do recommend him.
http://www.ford-trucks.com/forums/955188-the-5-star-mike-sticky-thread.html