Hmmm...as I too am puzzled by the failure discussed in this BBSC equipped NSX...I have my own opinions on it.
#1) Like already mentioned, the BBSC and/or tuning behind can't entirely be blamed (partially perhaps*)
#2) Ringlands failures can happen for a multitude of reasons...the mains ones being : Excessive cylinder temps/detonation/excessive cylinder pressures.
Here's the question I have for you guys....how many INTERCOOLER/AFTERCOOER equipped BBSC NSX's have ever had this type of failure ??
...I'm from the old school, which religiously believes in intercooling an F/I system. ESPECIALLY when converting a motor originally meant for N/A (i.e. 10.2-to-1 compression, less water jackets/cooling built into the heads ,etc...) to F/I.
.....obviously having a properly tuned AEM with a safe A/F ratio and timing settings will lessen the risk of detonation and reduce cylinder temps but intercooling *by itself* is just as effective (if not more) at lowering cylinder temps and the chance for detonation. At the very least intercooling will give you a MUCH larger safety margin (despite the HP increases) toward eliminating this type of failure ever again...IMHO.
I believe even 6PSI WITH AEM and proper tune @ 10.2-to-1 compression is pushing it without intercooling. While perhaps 7-or-8 PSI on the same set-up WITH intercooling would be still be more gentle on the motor than 6PSI without*
...personally, I wouldn't take it past 5PSI on the stock motor/pistons *without* intercooling. I rather do my re-build on my OWN schedule, not my ringlands