[Obioban]

I think he meant the s65 and s85 rod bearings are the wrong size, stock, and should be swapped with aftermarket.

Time will tell, but I think this is a misguided theory-- and as a result just put new OE rod bearings in my s85.

S54 rod bearings can have a hugely variable life span, depending how the car is driven. If you don't go over 7500rpm, they will outlast the engine. If you're on track and bump your rev limiter to, say, 8600rpm (and use it), you'll be replacing them ever 20,000 miles.

I do mine as oil analysis asks for them, which ends up being every ~100,000 miles (which, with my usage cycle, includes ~20,000 track miles... but my rev limiter is only 8300 and I try to shift at ~8000 if I'm not in a situation where it'll upset the balance of the car).

But, to my point-- I replaced the rod bearings in my M3 wagon's S54 for the first time at over 200,000 miles, and they were not yet end of life. It only saw a couple of track events.