agree with the logic, most people highly recommend the 15w50 motorsport for high hp road cars and race/ rally cars but these will always be brought up to temp before serious abuse

Hard to admit, but all my cosworths in the past 14 years ran on normal good quality mineral oil with regular 5k changes and felt much smoother than when it was swapped for the so called better synthetic oils - these were all standard 2wd cars though.

I used bog standard mineral oil to run in my latest car for the first 2000 miles then swapped to 15w50 mobil 1 motorport and it was quieter when cold on the normal stuff, but within a few mins of use its smoother on the mobil 1.

so I guess its just a case of letting them get up to temp for a few mins before using the loud pedal if you use the thicker synthetics

Also makes a difference if 2wd or 4x4, as the 2wd engine does not have the offset gudgeon pins so are all slappy when cold and the 4x4 with its improved ecu/lambda and knock sensor probably helps to mask the cold running noises to some degree until up to temp.

You also have the problem with the thinner synthetics of noisy tappets and more oil leaks and more oil usage due to the fairly slack tolerances of the cosworth engine as opposed to the modern motors about