Mainly it depends on the grade of the oil you're about to use. High grade oils are ment to be run in high temperatures and that only happens when you're racing. Basically it means that higher the viscosity rating, thicker the oil is. Thicker the oil, more poorly it can access narrow spaces and can protect the engine when it's cold. So unless you keep your foot down all of the time (which in a Cupra wont make you live very long), you really shouldn't use oils above 5W-XX. On the other hand, you shouldn't use too thin oils like 0W-30 or 0W-20. On high temperatures the oil gets too thin and can't prevent piston rings from touching sylinders.
The 'W'-viscosity value in multigrade oils tells you how flux the oil is in cold temperature and the following digits how thick in hot temperatures. Wider the span, better the oil. I'd have to say the best oil grade for the Cupra would definetely be 5W-50. However, me living in Finland and reaching temperatures -40 degrees celsius and I still have to go places, I'll use 0W-40. My Cupra still has 7000 km for its first oil change, but that's what it is going to get.
