hardtop adds rigidity.

[105e]

33 degrees here today so removed hardtop to go for a drive. Much more scuttle shake with it removed, it definitely adds some rigidity to the chassis i think.

[Carolyn]

33 degrees here today so removed hardtop to go for a drive. Much more scuttle shake with it removed, it definitely adds some rigidity to the chassis i think.

Yes, you're right about that. 

[Petrus]

With Dev´s door spacers, the difference is minimal.
The hardtop is sort o a brace fitted to the top of the windscreen where the movement in the tub is largest, but it is not a rigid fitting.
The door spacers are way lower but also a more rigid connection stiffening the tub.
Apart from the difference in steering response the reduced effect of fitting the hard top was for me proof of the door bushings.