IMO, asking what you run, without any sort of details on when your running it, or where, how you plan to drive, isn't super helpful.

Secondly, one man's notchy is another mans 'tight'. So your going to get plenty of un-quantifiable opinions on this topic.

Fun winter conversation anyhow

I wouldn't feel bad about running 20w50 in my race motor, that's been clearanced, that's warmed up to (oil!) temp before it's expected to take load, on a 20c day, then expected to take an absolute pounding for 10 seconds, and head back to the paddock with a cool-down.

Would I put it in my daily driver that starts in -20, and probably hasn't hit target oil temp by the time it's parked? No oil pressure/temp gauge? Not a chance. It'll get 5w30.

Horses for courses. Oil's a tool sized to fit a job, not an exact science.

FWIW Ryan, the time it takes to get 20w up to the head from a cold start would worry me. And depending on where your sourcing your oil for the turbo, it might be running without oil for a few seconds every time it starts. I'd side with you and say for a street car, in the summer, 10w30 makes a fairly well rounded oil in all but the most demanding heat/pressure.

Paul