Check out this REVIEW done by Tuned Daily Drivers
Check out this review of a stage 2 F10 M5 by bootmod3.
In the video there is a dyno run showing WHP!! Build cost and more.
Also a super close race between a stage 1 tuned M4!!
Tuned F82 M4 VS F10 M5 BM3 Stage 2 700HP!! + Build Cost!! MUST WATCH