Is premium fuel a requirement of the Overkill PCM in a N/A car? If not why run premium?
Im assuming that running premium all the time plugged the converter...
No. It wasn't the premium that plugged it. It may have been a "weak" cat to begin with and it could have reached the end of it's service life.
Or you may have been buying poor quality fuel that just happened to be 93 octane. Back in the day I worked at a gas station across from Courtland Center (back then it was the Eastland Mall) and the only difference between our 87 & 93 octane was that the underground 93 octane tank had 800 gallons of ethanol added to it (with no pre-mixing)when they filled the tanks. With the low margin on fuel for the gas station owners you need a station you can trust.