Best answer to this is information from Opie Oils , Tim & Guy 'oilman' .
They have had lab oil analysis on various such Ester Racing oils of customers samples .
These oils do contain 10-20% top group 5 oil basestock esters but don't know how far an improvement over a 504.00 oil because 504.00 does have ester in it , one of the reasons why it's one of if not the best manufacturer oil spec available .
Because it's so high and is keeping my vunrable PD camshaft happy I wouldn't bother with an Ester Race oil unless your S3 was going around a track .
They have had lab oil analysis on various such Ester Racing oils of customers samples .
These oils do contain 10-20% top group 5 oil basestock esters but don't know how far an improvement over a 504.00 oil because 504.00 does have ester in it , one of the reasons why it's one of if not the best manufacturer oil spec available .
Because it's so high and is keeping my vunrable PD camshaft happy I wouldn't bother with an Ester Race oil unless your S3 was going around a track .