So, I get free oil changes for life at the dealer I bought my 08 NAH from. They'll put in the regular non-synth 0W30 every 4K miles under this plan.

Questions:

1) They said they'd install MY synthetic oil if I buy it and take it in. What brands do you guys recommend that can be bought at local superstores? What are you paying per quart? How many quarts are needed?

2) Should I go with synth every 4K miles (assuming I'm paying just for the oil)? Or, would people still recommend going longer between changes?

3) Does anyone have any concrete data on savings (FE or otherwise) in the NAH when using synth 0W30 vs. the non-synth?

Thanks!
Eph

Hand calculated numbers, not trip computer data.