Afternoon guys, I've recently purchased 4L of oil for my car, a 2012 S3. As expected, my car uses a little bit of oil and needs a splash every few weeks to keep the levels up. The car came with CASTROL EDGE PROFESSIONAL 5W30 LONGLIFE, I managed to pick up a good deal on some on Amazon, however I've just compared the bottles when checking the oil and I've actually bought the normal CASTROL EDGE 5W30. The question I have: Is there any real difference between these two? Yes of course there is but anything that might damage the engine? And if so, anyone need 3.5L of Castrol Edge for 25 quid?!