Cold Pour Points and hot HTHS
M1 5W20 EP, PP = -42C, HTHS = 2.75 cP
M1 5W30 EP, PP = -40C, HTHS = 3.0 cP
M1 5W20 Regular, PP = -43C, HTHS = 2.75 cP
M1 5W30 Regular, PP = -42C, HTHS = 3.1 cP
So the 5W20 is always a little bit better in the cold over the 5W30 (give the same flavour of M1) but interestingly the regular M1 is a little better than the Extended Performance M1. But there is not much in it looking at the pour points. But this answers your question.
To be honest I would go the regular vanilla M1 5W30, as it's PP is as good as the M1 5W20 EP, but being a 30 grade it has a higher HTHS for hot & high load performance. This still meets your requirement of using a M1 product at your mate's shop and still following the car owners manual.
You know, time and time again, regular M1 5W-30 impresses me as a well designed and well balanced product. I'm a Castrol, Valvoline and Penrite man myself, but hats off to a well designed oil that is regular M1 5W30. I may have to buy some one day.
M1 5W20 EP, PP = -42C, HTHS = 2.75 cP
M1 5W30 EP, PP = -40C, HTHS = 3.0 cP
M1 5W20 Regular, PP = -43C, HTHS = 2.75 cP
M1 5W30 Regular, PP = -42C, HTHS = 3.1 cP
So the 5W20 is always a little bit better in the cold over the 5W30 (give the same flavour of M1) but interestingly the regular M1 is a little better than the Extended Performance M1. But there is not much in it looking at the pour points. But this answers your question.
To be honest I would go the regular vanilla M1 5W30, as it's PP is as good as the M1 5W20 EP, but being a 30 grade it has a higher HTHS for hot & high load performance. This still meets your requirement of using a M1 product at your mate's shop and still following the car owners manual.
You know, time and time again, regular M1 5W-30 impresses me as a well designed and well balanced product. I'm a Castrol, Valvoline and Penrite man myself, but hats off to a well designed oil that is regular M1 5W30. I may have to buy some one day.