There have been a few threads this holiday about long life service intervals, costs and what they involve so I thought I would make a few points. This is just a personal opinion but if you plan to keep the car i wouldnt even consider Audi long life oil or service intervals. Last year when i had all the trouble with my engine I was called into Audis to discuss the problem and the cost which was mounting up alarmingly at £1400 a day. I had a meeting with the service manager and the chief Tech to try and work out a way forward given we still hadnt diagnosed the problem and the bill was fast heading for £4k. The tech told me that my engine was very badly coked up in the oil ways and surfaces in the lower engine and heavily varnished in the upper hotter areas. This was either due to poor quality oil or i had been thrashing the engine relentlessly and had cooked it. I explained that the car did a 10 mile commute in Surrey each day where you are lucky to get above 40mph and all the oil changes had been carried out by Audi to the schedule. At this time the car had only done 38k miles and it was the worst case of varnished oil/engine he had seen. He basically said they were going to see this more and more often with the Castrol long life oils and it was a problem they never had with years of using Mobil 1. Eventually the fault with my engine was diagnosed as a stretched timing chain, a item that should have lasted the life of the engine but fail at less than 40k miles. Several other guys here were having a similar problem and an article was found in German detailing the problem in a engineers report with pictures showing how the oil had burnt soot black and coked on at crankshaft level and had set into a honey gold varnish higher up where the heat of the cylinders had cooked the oil. Several problems arose from this including a molecular change of some steel components including timing chain and tensioners etc and a loss of lube properties in the Castrol oil. The article is in PDF form so I cant copy the pictures but you can see them on this link. http://www.a3quattro.de/pdf/Bericht_VR6_3-2_Kettentrieb_onlineVers.pdf Its 13mb so give it a minute to load. Note the end shot of the engine on page 55 The crud build up at 60klm on page 78 using Castrol. Note the final comment which is a recommendation to use Mobil1 which takes us back to the advice of the Audi tech. Personally I think Audi are storing up huge problems for the future with Castrol and given it cost £30 and they charge £100 its difficult to see why they gave up with Mobil1 except that Mobile1 is more expensive so their profit margin would be less. You get what you pay for and as someone who is an engineer and has built and raced motorcycle engines I never skimp on oil or tyres period. Some of you will see this as Paddy just moaning about Audi again which is fair enough but dont forget after looking at this PDF Audi UK do not except liability for a problem here !