Good question. Haven't heard of any issues yet... well the GR86 has the RTV gasket leaking into the block causing failures here and there. The only rock solid Motor still with no defects or issues is the Great K20c in the FK8 and FL5 Type Rs.
I just changed my oil at 1800 miles after breaking it in. Whew! Glad to have synthetic lubing the metals now! And glad to accelerate with conviction now haha .