As a follow-up, I still believe in using Big-Serts ONLY when needed to repair a previously repaired thread, and only on holes that needed them. I would really rather have a smaller, less-invasive insert that does the job (like a regular time-sert) than immediately go for the stronger, bigger, BigSert.

I have installed regular time-serts in all 14 holes of 8-10 M54 blocks and have not had a single one that failed.

This fellow used a competing insert from Huhn Solutions (https://www.huhnsolutions.com/) which has a bigger footprint than a time-sert...He ended up cracking his M54 block with the Huhn insert- leading to an external oil leak on driver's side (LHD) - and has attempted to fix it with JB Weld. I worry the same thing could happen with a big-sert.

https://youtu.be/nLSX1UAN2Pw