In the C&D article on the 5.0 engine, it said Ford skipped a full 12 month prototype phase to fast track this engine. I don't know about you, but Ford doesn't exactly have the best history of making awesome products during the initial roll out, especially if they skipped a full year of testing. Modeling and simulation is great for proving out the design, but the manufacturing phase is quite a different beast - you have to make sure all of your suppliers are making products that are up to snuff. I'd definitely wait about 3-4 MY's before buying a 5.0 powered GT. The 05-08 4.6 3V had spark plugs that would break apart. It took Ford roughly 3-4 years to release new cylinder heads with the new spark plug design - and that's on a design that was already 3 years old in 2004 (so basically they got a fix about 6 years after the initial release).