Is component's thread torque a factor in how 'stiff' a bike rides? Would a racer want higher torque? Is higher pressure into the frame going to reduce vibration and hence improve stiffness?
There is an extremely small stiffening effect because the interface contact area increases slightly. But in aerospace we usually consider this a negligible effect. To make a system stiffer all the parts have to become stiffer, which of course does not happen because you tighten a bolt in the system