I just got a custom tune for my '01 V10 from Mike at 5-star tuning, using an SCT X3 tuner.
5 Star Tuning | Custom Dynomemeter Chassis Tuning Products and Services
My 0-60 times were around the 10 second mark (9.7 to 10.4 using datalogging yesterday, and 9.9-10.0 using stopwatch a few days ago).
The 0-60 time is now 9.01-9.04 seconds on his 87 octane performance tune. That's around a 10% improvement in acceleration times. For a 6900 lbs truck with 3.73 gears, that's a huge difference.
Of course, that doesn't directly apply to a 2008 5.4, but it does give you an idea what can be done. And Mike has had great luck with the fly-by-wire throttle response.
