[Fixed, using a Time Sert kit] M18 Oil drain plug stripped, recommended solution?

[haigha]

After 18 years and 18 oil changes, at 42k miles, the threads in the oil pan for my 4.4i N62 oil drain plug are failing. Always changed by my mechanic friend, except the first three at the dealer, under the service agreement.

There was a small oil leak I noticed a day after the last oil change. I checked with my torque wrench after seeing the leak. It wasn't over-torqued (it was just under 25 N-m, but after tightening it to spec, it was still dripping the next day).

Picture of the damage:



I've done some research. I'm posting here for advice and so that anyone else searching specifically for the M18 or N62 can find a thread with links in it more easily.

The two main solutions I'm considering are getting the M18 Time Sert kit, or using an M20 tap and going with a M20 plug.

Here are a few links for Time Serts:

https://xoutpost.com/bmw-sav-forums/...ert-gurus.html

https://www.timesert.com/html/mtrcsert.html (M18 x 1.5 kit needed)

https://belmetric.com/time-sert-thre...ric-big-serts/ (no M18 Big Sert for some reason)

I found this video on the Lisle kit which only works up to M14, but shows the grease trick to catch the swarf.

https://www.youtube.com/watch?v=1xg2Zo-GmGo

https://www.amazon.com/Lisle-58850-O.../dp/B000J19K06

The M18 Time Sert kit is currently $242 (edit: increased to $265, two weeks later):

https://www.amazon.com/Time-Sert-181.../dp/B003W62AZ2

If I go with this solution, I'll likely sell the kit after verifying the problem is fixed. I saw a video using grease to catch the swarf while drilling and tapping the new threads for the Time Sert (also recommended by @wpoll in the Xoutpost link below).

The threads on the original oil drain plug look fine, but I'm considering getting a new one from FCP Euro:

BMW-07119905428 https://www.fcpeuro.com/products/bmw...-07119905428oe

I saw @wpoll's posts here. Interesting inexpensive fix with the M20 tap and M20 plug. My concern is that if it doesn't work or the threads fail later, there won't be much room left for another solution.

https://xoutpost.com/bmw-sav-forums/...in-plug-2.html

Any thoughts or recommendations? Thanks!