Originally Posted by Maxwell Power
I picked up 40whp and spooled 250rpm faster when running 21psi on a GT35R from the factory header with Grimmspeed Crosspipe to this header. Most of my customers see similar results. That would tell me, no, it isn't hurting spool and yes, it is improving flow.
My experience is the same. The only time smaller runners help is for smaller turbos. There is a point when the runners become the choking hazard of the motor.