I recently purchased a 2005 Dodge Ram with the 5.7. The truck does not have MDS but 5w20 oil is recommended. I think this recommendation is due to CAFE pressures and I was planning on running a 5w30 oil. Here in Canada a lot of synthetic oils are overpriced and so I am leaning towards conventional oils. There are 120,000 km on the truck and it is in very good condition. What do you guys think?