may be stupid but just an idea i had. your sai as i know pumps extra air into your exhaust side of your cylinder head... extra air to heat up the catalyst.

SO lets say with a SAI delete. could you then revert back pressure to your SAI ports.

in my mind this would result in keeping the turbo spooled slightly better on quick shifts rather than reverting it to the intake.

or maybe the colder air would be bad to expose to the turbine wheel and this is just stupid