HI all, Just wanting to pick peoples brains over an issue i've been trying to sort for awhile.  I have an fg mk1, 12psi actuator on a gt3576 with 37mm port, 4inch dump and high flow cat with a full exhaust.  For a long time now i've been trying to tune out 'overboosting or boost spikes' on gear changes , mainly 1-2 and 2-3, with varying success.  I'm running 16psi to 4750 which tapers down to 10psi at 6000rpm.  By doing this i've managed to keep the spike between gears to about 18.5-20psi.