Turbo_sloth

I fitted coilovers at the weekend and dropped the ride height 40mm and found under throttle I was getting a slight knocking noise and vibration, so I raised up the height 15mm and found it less severe and frequent (only driving up hill).

So I've ordered driveshaft spacers concluding this must be the issue. But I'm wondering what height people have got away without them and is there a chance if I had the spacers on and raised the car up to stock height would it cause damage with the spacers in?