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 5W-30 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.