The problem you have, as I understand it, is that you are virtually guessing as to what replacement suspension setup will work - notwithstanding the recommendations folk have made here, but unless they are for the same vehicle with the same wheel size, then by definition they can only be 'right' to a certain extent.
The second thing I have noticed is that you need to consider 'high speed' and 'low speed' damping as two separate things.
At the risk of stating the obvious, the damping resists the natural tendency of the spring to oscillate. Too soft and the spring acts like a po-go stick, being relatively unrestrained, and bouncing 2 or 3 times before it reaches its resting position; too firm and the damping piston does not have a chance to move up or down enough before the next bump so it 'pumps' down the barrel giving less and less travel.
The situation is further complicated by the fact that the compression stroke of the damper may be a different rate then the unloading stoke, so you have two parameters to control!
For example, my Volvo XC60 has a harsh ride around town yet lacks precision and wallows at speed on motorways. So ideally it needs softer low speed damping (towns), ideally on the compression stoke as the wheel comes out of a pothole and is forced up, and firmer high speed damping (motorways), where both compression and rebound movements need firming up.
So where does this leave you? Well when I raced bikes I would visit a suspension expect who would change the damping by altering the number or holes the damper oil had to flow through as it moves up and down. This worked well for motorcycle front forks, but the rear damper was usually just replaced with something more appropriate.
The difference transformed the bike's handing.
Therefore, IMO you need to visit a suspension expert and explain what you what. They will test drive your car and make an assessment of the high and low speed damping themselves with a view to installing something more suitable to your particular requirements.
Racing team outfits usually have the experience to do this, providing you explain it’s for a road car!
The danger is something folk have already highlighted – you get given very firm suspension because it’s thought to be ‘sporty’. The dilemma with this is that on a race track were most of the suspension’s work IS done at high speed – you are racing flat out after all – what you and I would consider to be overly firm suspension is just what you need! So it’s not a perfect solution.
My alternative suggestion is that you drive different suspension setups for your car, say the “Elegance” version car rather than the Sport, and if you prefer that then specifying new suspension would be easy. Other than that you could use Audi suspension (or BMW, etc etc) but you would need to a) know the dimensions of the shock absorbers and their end fittings, and take the setup from similarly sized/weight vehicles.
Frankly the latter will be difficult, so in conclusion:
I’d seek expert help from a suspension tuner, who might even be willing to let you ‘try before you buy’. I don’t envy your mission
Cheers,
Robert
