I think the NA 6s have it. but I know the Phoon doesnt. im pretty sure it could be an overlap factor. the 3540 spools early, and im guessing due to that fact, they dropped the long runners on the turbos eg: this is a dyno sheet of when the EF was N/A (and running an AFR in the 8s, but we can ignore that cos it doesnt affect rpm switching) as you can see, there is a distinct drop of power at the point of runner switching