Smoke issue

Am very familiar with BMW's and sold tons if them, usually on inline 6 motors it is pretty easy because there are no turbos and PCV issues are infamous. So I replace them and it goes away. But with these v8 twin turbos which are infamous for smoking it is more difficult as it could be the valve stems.
So basically the car starts runs and drives great with lots if power and no codes.
If you leave it idling for say 10 minutes and then hit the gas you get a puff of smoke. Then it goes away.
How do I know whether this is a PCV, valve stems, or even rings or head gasket. No overheating.