I changed out to solid mounts in 2001 when my GT6 failed its French MOT. All the talk of different rack heights and use of jubilee clips worried me somewhat so I went and looked in my old parts box ( I never throw anything away ) and compared the old mounts with the solid ones on the car - the height is identical. I checked to see if the rack had moved - Nope. If it hasn't moved in 17 years, I doubt it will move now. I'll probably put a clip in for security just in case. TP