There isn't a difference. The manufacturer spent a lot of time and money getting the suspension how they wanted it. Lowering it does little more than **** it all up. Getting the whole lot replaced might at least give you acceptable handling - assuming the correct coilovers and setup - but it still makes your car look stupid. If the vehicle is genuinely set up for track, then still looks stupid, but at least there's a reason. But just putting shorter springs on is for idiots.
I've being reading up and talking to specialist to find the most suitable ride heights for my car.
An M3 CSL with it's 19" wheels sits at a height of 665mm front and 660mm rear from floor measured to arch. About 345mm / 340mm measured from centre of wheel to eliminate wheel/tyre size/pressure.
This is a great handling car which BMW design with track in mind, but even this can be improved on for track and fast road whilst still maintaining comfort, it's just not cheap. To maintain comfort you need expensive coil overs such as KW, AST, Ohlins, Nitrons, Motons etc. So 2-5k in suspension and ideally smaller wheels 18"
In short Thorney motorsport, Simpsons, centre of mavity, Spires, wheels in motion, Powerstation are all pretty much recommending the same which is:-
645mm front and 640mm rear or 330/325mm measured from centre of wheel and then corner weight. The result is a much lower car but not slammed. Owners with this and myself it's simply a revelation, great improvement.
They key to success is keeping the suspension arms parallel to the ground so they have good range of movement, people who slam cars means the arms are not parallel and as such the suspension can't operate properly.
But lowering works as long as you do it right, consider a stock M3 they are even higher than CSL from factory, so a good 30mm drop will improve the car a lot if quality items are used.
Even cars from the factory which are sporty such as M3 can still be improved if done right, it just tends to be expensive in parts and setting up.
It is simple physics a lower cog improves handling as long as you don't compromise the rest of the suspension and introduce to much bump steer etc and remember going lower means more front camber sometimes too. You have to remember changing ride height has positives/negatives hence each car has an ideal ride height, lower normally means harsher ride but better performance. Though some setups can go lower and also improve comfort too, you get what you pay for with suspension.
Problem is as per the car posted by OP some people simply think go as low as possible and slam it, this does indeed ruin the handling and will actually vastly reduce the lifespan of the suspension.
A lot of standard cars are too stiff and crash and bang over British roads there's no way a car with virtually no suspension will handle well on a British road.