I guess their marketing department is doing their job if they got you to purchase the engine oil just because of the word sports. Castrol Edge cost more than Castrol Edge Sports. Castrol Edge Sports used to be known as Castrol RS and I've used it before. Power lost.. substantial.

Reason for sports use.. simple. When the car is used in the track, the engine temperature goes so high that it does not matter what viscosity you use, they all end up the same. It's so hot that they all end up like water, even with 10W-60, so it works just fine in Sports but not for street applications.

Try changing to a lighter engine oil and feel the difference. Then ask yourself a simple question. Why is does the engine feel heavier with the heavier oil? So much more resistance in the engine that it is felt by the driver.

Well, Edge Sports is good but not the best around. It's one of the cheapest fully synthetics around because it's not Ester based. The best ones around are Ester based. Also because they don't have proper distribution in Malaysia, there is too many fakes in the market. I've personally encountered the fake ones and lost about 1.5L in less in 1000km mileage. Took it out immediately and never use again. Furthermore I've been buying from the same shop without issues previously. Currently I'm using Petronas Syntium 5000 0W-30 and damn it is nice. I also chose it because I can get 5L packs (4+1) and that only their biggest petrol stations stock it. Furthermore it's one of the few companies that make the same grade with different viscosity.