Ok, at what point do I need to switch to premium gas (91-93 octane).

Everything on the engine is stock now except for a K&N drop in filter and a
2.5" downpipe. Stock CAI box has been opened up a bit. Oh yeah, with the DP and K&N I don't need to flash the PCM yet do I?

Future mods include a HVTB, spacer, HVIII, ER Ratio Rockers, 180 Temp, 1 step colder plugs, a WizAired CAI, and a PCM flash.