[ainarssems]

I will just add a couple of my thoughts:

1. About engine flush. I don't think it is needed for engine and oil made in last 30 years which has been regularly serviced and not overheated. Flushes were designed to dissolve burned on deposits from old mineral oils. Modern oils have additives that take care of it and should not be a problem for modern synthetic oils if they have been changed to schedule and engine have not been overheated causing oil to burn on. In the rare cases if engine oil is too diluted with unburned fuel they may even cause damage to engine by diluting oil even further. It's an unlikely scenario but on diesels with DPF being driven short distances oil contamination with unburned diesel can reach over 40% between oil changes. In most cases flush will not do any good or any harm, just a waste of money.

2. I like the idea of 2 oil changes but I do not think it is necessary, the oils are designed to have up to 40% dilution and if you change them at intended intervals or sooner you will be OK apart from some rare cases on diesels with DPF which are driven short distances.

3.Dealer oils like Quantum are designed to be good enough for most of their cars most of the time but they are not the best. So certainly there is a room for improvement.

4. Many of modern oils are designed to meet emissions and fuel efficiency, they meet minimum requirements for engine protection but they are not necessarily the best. For the England you do not need 0Wxx or 5Wxx oils, it's just that they are thinner so introduce less resistance and require less energy so are better at fuel consumption and emission but are not necessarily good for engine. That being said modern engines are made good enough to make it through warranty period even with lesser oils. I don't think manufacturers are particularly interested in what happens after 100k miles.

Just to end this I think Quantum Longlife III is a good oil for every day driving and occasional push but should not be used for 18k miles which manufacturer allows but changed at least once per year.

If you take money out of equation 10W60 oil should be better if you drive hard and everything else is equal.

You may also consider molybdenum disulfide powder additive to the oil which will reduce friction, wear and temperature. Don't buy the liquid ones as they will just dilute the oil, get the powder.