What Tony said ^^^^^
If it's mainly for gear changing, try changing gear without coming completely off the throttle. Takes a bit of learning but you can eventually get your foot to automatically mimic the right place so as you bring the clutch up and power back on, the revs are more or less matched. Kinder to your turbo, engine, clutch and gearbox and keeps the turbo spooled up too, improving your acceleration times.
If it's more for when you come off the loud pedal to slow down for a junction say, you could add a throttle damper, this would slow the last few mm of throttle butterfly movement as it approaches the idle position, allowing the turbo to slow down a bit and come off boost more gently.