If you shorten the spring, either by cutting or compressing, you will lower the car.
The answer to your question seems so obvious to me, that I think I may be misinterpreting what you are asking....can you ask again, using different wording?

One thing that is rarely mentioned about the TLS spring used in the C4 is the packaging consideration. This spring is a horizontal spring whereas a coil spring (unless used with mechanical linkage) is a vertical unit. There is more room to fit it into the chassis.
A short coil over will fit, but brings with it too many maintenance issues to be viable for a mass-produced car being sold to the motoring public. What works great on the track on weekends does not usually work all that great on the weekday commute.

Because the C4 has very little room under the bodywork for lots of wheel travel, a very stiff spring has to be used to keep wheel travel at a minimum. Stiff springs require stiff shocks to control. Results: a pretty hard ride.
I subscribe to the same school of thought as Bogus: soft springs and stiff shocks provide the best compromise between ride comfort and all-around handling both on smooth and rough roads. Unfortunately, the C4 will not allow soft springs, so it handles well on tabletop tarmac and less well on stutter bumps....unless you can dial the suspension components in exceedingly well....

Larry
code5coupe