On the next oil change in my '09 Crown Vic, I am planning on switching to Mobil 1's 0W-20 AFE from my current fill of Mobil 1 5W-20. For those of you that have this engine and switched to the 0W-20, were any noticeable differences encountered? i.e. start-up noise, fuel economy, consumption? I compared the viscosity numbers between the two and the 0W-20 is slightly lighter than the 5W-20...as expected. Two members here, 2010 FX4 and Tig1, have demonstrated the benefits of using Mobil 1's 0W-20. It appears to be an excellent oil with great basestocks and cold flow properties.