I think a lot of folk think a bit too hard about these things,

A decent quality upgrade will be better than oem,
A high quality upgrade should be better,again!
You could buy an ohlins or Hyperpro or Wilbur’s from any retailer,
They ask a few very basic questions and the shock is built at the factory then delivered to the retailer.
It transforms the bike says the customer

,
So,one of the questions asked,
How much do you weigh?
Passenger or not,?
How much luggage?
Let’s look at this,
Rider 100 kg
Passenger 100 kg,50% of time
Luggage 30 kg 30 % of time
The spring rate is fixed,preload can only alter the ride height.
The spring fitted to the shock needs to deal with a load ,plus or minus 130 kg,which is a fair bit more than the original specified rate.
Solo,the spring is too strong,
Loaded too weak.
So how has the shock transformed the bike?
Now I’m no expert,but to my mind,the difference is in the high speed damping and blow off rates of top end shocks.
Maybe denzo would explain it all better.
But the buyer experience,
where the fucked oem shock felt harsh and you feel a general roughness from the road.
The quality shock is like a magic carpet,this isn’t down to the spring ( although the top end shock would have a more linear one perhaps and as stated above this is a compromise on a mixed use road bike)
This is down to the damping quality of the unit.
On a big hit,the shock needs to blow off and compress instantly,
Then recover to damp rebound ,
Then there’s the really small stuff that causes the rough sensation.
So there’s a lot going on ,the amount of damping oil is ,notalot,
So one would expect that a shock,doing a lot of work,needs to be serviced.