One thing to note when evaluating tyre and suspension performance together is that lower profile tyres pass more low amplitude/high frequency movements to the springs/dampers. This is why low profile tyres and hard suspension results in a jittery ride - higher profile tyres are able to absorb (to some degree) small changes in the road surface profile, leaving the suspension to deal with only larger road surface variations.

Also when considering suspension, you have to realise that your springs have a dual purpose - the first is to keep the wheel in contact with the ground, the second is to keep the chassis off the ground. It is primarily the spring which absorbs impact from road surface changes - this is why progressive rate springs work (they allow quick deflection for low amplitude/load deflections, but as loads increase they firm up (to prevent body roll in corners or "float" when there are larger undulations). Spring compression is controlled primarily by spring rate. Dampers are primarily there to control the rate at which springs expand after compression (to prevent bounce associated with sudden unloading of the spring or return of force as the spring uncoils after it absorbs compression energy), though they can also be used to change compression rates as well (by resisting compression force encounted by the spring) - this is more unusual (and generally only available as something you can influence on 3-way adjustable suspension - 1-way adjustable is height adjust only, 2-way adjustable is height plus rebound).

And of course, to counter body roll, you can increase swaybar stiffness (often adjusted by changing size) - it's not uncommon for cars that race on very even surfaces to have massive swaybars but relatively soft suspension.

None of which at this point is relevant to the OP unless he's also looking at suspension changes.