It's all true, for what it is. The thinner rods were used in ALL B230 and B230 turbo engines up to about 1990 as you see. They are mostly vulnerable in turbo engines with the boost turned up, primarily when detonation/pre-ignition puts heavy stress on the rods.

Not as scary as it sounds unless you push the engine hard (by this forum's standards; turbobricks.com is another story.) My 1986 turbo has over 500,000 kilometers on the original (small rod) bottom end and runs well. I have the boost turned up to 12psi and other moderate performance mods and sometimes drive pretty hard. Good gas and attention to tuning are important.

OTOH, I recently took apart a 1985 B230FT which had excellent compression and leakdown numbers, had been running great, and found two bent rods. Might have gone another decade, or one more hard run.
--
67 144, 85 740T, 86 740T, 91 945SE, BMW R69S, R60/2