.255" or .65 mm should be fine to run with DLI on stock coils. I run this all the time and don't have any issues. I immediately notice issues if my gap gets to 28psi.
Since you are on the AEM, you need to log your timing and A/F to see wheter this could be related to the crank sensor reluctor ring. This ring has a history of falling off or being worn through when the front main seal fails. It is noticeable at idle with a mis, but you won't see any issues until under boost. THe only way to see if this is operating correctly is to either tear down the front of the engine to inspect the ring or use the toyota scan tool.
This failure I listed will cause the car to go pig-rich under boost.