If you live in the ridicuously hot parts of AZ, you can move up to the 5W40. If you spend any amount of time in excessively colder areas, stick with the 0W40.
All of the higher priced oils, i.e. Gibbs DT40, Motul ot Total are excellent products. They all have higher levels of Zinc in them that have been proven to be a beneift to the M96 engines. If you can afford them, use them. Some people do an oil flush, prior to upgarding to the pricey stuff first. Check each manufactuer for a suitable flush oil. It is usually a break-in oil. But that adds another oil change and filter to the cost.
If you are on a budget, use the Mobil 1. If you think your engine is suspect, send an oil sample to a testing lab and get an idea whats in your oil now. I use Blackstone. I also use Mobil 1 0W40 from Walmart.
Having typed all that, Release the hounds...
