Maybe you should not go above Tiagra/105 level for road components since this is the point where reliability might get sacrificed for performance and weight reduction. The same probably applies for mtb.

You do not need shock absorbers unless you have health issues or plan to regularly ride on bumpy roads. They cost weight and money. Also carbon fork and seatpost can reduce vibration, but I have no idea about their BIFL properties.

Edited typo