I have been running synthetic oil since 1000 miles. Mobil1 0W-30 and Motorcraft filter from 1k-40k and never experienced a problem. I did the Amsoil engine flush and switched to Amsoil Series 2000 0W-30 oil and Amsoil SDF-11 filter at 40k and now have over 80k miles. No engine problems, I get 29mpg on the Highway. I change the filter at 10k and the oil at 20k. Amsoil says you can go 25k between oil changes.
FWIW, I use Redline Water Wetter and my engine runs noticeably cooler.
Amsoil rulz!
