firstly you need to get a few things into perspective..
UPRATED shocks.. hmmmm. a catch all phrase...
there are shocks that have increased rebound settings for use with stronger springs.. the shocks only purpose in life is to control bounce nothing more.. more correctly, to control the oscilation of the spring in a known manner.
If you increase the spring rate, you would need to increase the rebound of the shock.
Then you have shocks that are physically shorter so that there is no binding (hitting the stops) on deflection caused by a shorter spring.
If the spring is shorter, but the same rate, then shorter, std setting shocks are needed.
If the spring is uprated, the shock needs uprating and matched for size (how far it can compress)
then, we come to the oft asked question you pose.. will it handle better..
There is no fixed answer to this, it depends on the original setup. If the original setup was designed to accomodate body roll (as in a 172) then by lowering and stiffening you are limiting this roll, good ??.. nope, not necessarily...... as the weight is transferred to the loaded wheel the suspension compresses and causes a change in camber (negative), this is a FEATURE, ie - needed... to not allow the depression of the suspension to roll on neg camber on the loaded wheel will induce understeer.. not assist it.. with a change of camber, you can compensate, but, you cant easily change the camber settings or rates. The other tendancy is for the lowering to increase neg camber (depending again on suspension design!) gloabally, this can be good, but can also mean a more sudden breakaway at the limit with little , if any feel fed back to the driver.
If the car has a tendancy to maintain a flatter camber in roll, then it may be seen as benefical to the handling by reducing the body roll and weight transferance (as in the lower spec clio models), what you ae doing is reducing the change to maintain predictability.
Your shocks play no direct part in this at all (it is the spring that does the goodies) the shock is there to damp the movement, so is obviously dependent on 2 factors only, length - open and compressed, and rate, compression and rebound.
So, an answer to one of lifes great mysteries lol.. as in, will loweing improve my handling..
Not necessarily...