Near all vehicles engines are bench run in before being fitted to the vehicle, in this proccess they are run on mineral oil (usualy SAE40) for around 30 minutes and are driven at various load points and RPM to seat the rings and cam followers ectr. During pre-delivery service near every performance car will be required by the dealer or agent to be filled with the specified synthetic oils., most manufacturers will void your driveline warantee if they pick up you have used mineral oil in a engine specified for synthetic.
Ian has shown me first hand probably 10 or 15 SR20's he had and which oils they were used in each, You can visibly tell what motors use what oil by cam condition and big end wear let alone the TERRIBLE sludge particualy from magnatec. He told me somthing very simple, 90% of engine wear happens on start up, synthetic oils protect up to 200% better than mineral oil by creating a protective barrier on the bearings and cams once the oil has run off, when running Synthetic it also helps keep the dirt in the oil (opposed to creating deposits) so it can be caught in the oil filter like it should. Last benefit I can remember him telling me about was that it doesnt break down as fast, especialy with the fuel dilution seen in turbo cars running very low fuel ratio's.
I asked him after reading this why our cars were not spec'd to run synthetic from the factory, he gave me a simple answer, technology vs. price. Now days its far more cost effective to receive the benefits as it was 10-15 years ago when synthetic oils were still in their infancy and major over priced, probably why near every performance car and loads of normal cars are spec'd for synthetic from the factory (including Nissan, Ford, Volvo, Audi, BMW, Toyota ectr)
