Swapped to M1 0W40 on the Z a couple years ago and Blackstone reports have been great.
40k miles or so but heavy track use.
It should be a fairly safe swap from 5W30 to 0W40 for most cars.
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@stupidtoycars | My track vids
09 7AT|MCS 2WNR|Topgunz Rotrex|Ecutek (Eugene)|Maxxis RC1|Titan-7 TS-5|OSG LSD|Rear Mount Derale Oil Cooler (WIP)+25 Trans Cooler|Fismo|G-LOC R12/R10|Zeta III L|NLR Wing and Splitter|CJM Pan and Fuel Hat|Radium Surge Tank|AP Racing CP9668
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