Hello, I'm a new member to this site and have a question. I am a US DoD contractor in Germany and have recently bought a 2005 VW Golf Plus. It has a 1.9 liter diesel and I really like the fit and finish, as well as the great fuel economy. The car was dealer maintained and has had all of the periodic scheduled maintenance performed. I like doing minor work to my cars, which includes oil and filter changing. Currently, the car has Castrol 5w30 SLX Professional Powerflow VW Longlife III running in it. This oil is very expensive (by US standards), like around 25 euros a liter. I've seen in a store recently 5-30W oil by Blue Moly; it sells for about 15 euros for 5 liters. I'm spoiled to the US prices of about $6 per quart for 100% synthetic oil. I know this the oil listed above is recommended by Castrol, but can anyone tell me if I can use another very good quality oil, but at a much lower price? Brand name and type oil would be appreciated. Thanks in advance.