
We need more stock results for context but it look like the M5 Competition is good for a few tenths and a couple miles per hour over the standard F90 M5.
Conditions and tracks differ but the Competition and JB4 tuned cars are eerily close.
Competition F90 M5:

JB4 F90 M5:

BMW is giving you a tune with a warranty. If you want to go beyond this no reason to really opt for a Competition M5 as the warranty appeal is gone.
10-second pass:

vBulletin Message