Ha ha, to revive this thread and cause some more disagreement
symonh2000 is right that a 0Wxx rated oil will not be too thin.
I don't know how any of you lot can think it will be 'too thin'. Just to clarify, I think you mean when operating normally. If you look on the Mobil website, you will see the viscosity is about 14cSt at 100°C (10°C off normal operating temperature). If you compare this to any other xW40 rated oil, you will find that they also have a viscosity in the 13-15cSt range (cSt stands for centi-strokes and is the measure of viscosity if you use the test specified in the SAE standard - which all engine oils do). So to say the oil is too thin is cobblers.
You may find that the engine oil lubricates just too well (although I would love to know how)? A friend of mine is very into racing pre 80's trials bikes, and some of the engines he uses must use a mineral oil because the synthetics oils are that 'good' they cause bearing skidding, rather than protection by allowing the bearing to roll.
What you may also find is that the 0W part of the rating (i.e. the bit when the oil is cold) is too thin. I have this problem with the Volvo, because when the car is cold, the oil is that much thinner (than, say 10W40) and it leaks due to worn engine seals. This gives the impression on my car that the oil consumption is high, when infact, my car is just loosing the oil due to worn engine seals (these will be replaced in the next few weeks, and when the synthetic 0W40 oils still get used at a rate of knots, I will eat my words
On thing is for sure though, the rating at the beginning should be as low as possible to give the best cold-start protection.
They don't bother with this on really high end racing engines, as hot oil/pre-heating the oil is used before start because a higher viscosity grade is needed. Because you can't get really big gaps in the ratings (e.g. 0W60 does not exist) the oil is too thick at low temperatures to provide adequate protection. The reason a high rated oil (e.g.60) would be used is because the engine would be operating at a higher temperature (e.g. 105°C) than a normal road car. The high viscosity oil would be chosen to MATCH the viscosity of oil the engine would need at 90°C (normal) so for example, if the viscosity required at 90°C was 20cSt, then the same engine at 105°C would need a more viscous oil to also provide a viscosity of 20cSt at the higher temperature. This way the fluid flow rates will be the same.
Unless you always thrash the knackers off you 2.0 TS, I would doubt a 10W60 is the best choice (too thick at 90°C i.e. the temperature of YOUR engine) - but this is only a guess, and if Alfa say otherwise, don't listen to me