OP- The spark plugs your running are stock heat range, and should be one step colder (8 rather then stock 7's) That's one problem, the other is the gap 0.36 is too much to not rule out spark blow out as a possible issue. You should be gaped .30 min at your boost level to rule that out. If you have old/weak coil packs I imagine the spark plug gap becomes even more crucial. This gap issue would only manifest with the belt on/boost, which is why im mentioning it along with your other troubleshooting you have done.

 

UPDATE: No more issues with Infintiy Ems. It was that darn Fvm module from SOS.

 

Bad internal map sensor voltage setting possibly on that fvm unit. If the stock ecu sees higher voltage then stock from positive pressure it will cause the ignition to break up. There is a way to check/correct this I understand, just not sure how but SOS likely does or sends it off to the manufacture. Have always been curious to see how these fvm units behave on a NA set up with the fuel and vtec correction. Feel free to PM me if you want to offload it. Id like to experiment, and throw you a few bux