Of course you can set the suspension slightly lower and run it like that, just fine - the world will not end, you will not die, you need not even damage the car... All depending on how far you lower it.
People lower cars all the time. There are good ways to do it, there are bad ways to do it. There are amounts you can do it by which pose no damage to the car, there are amounts you can do it by which do pose damage to the car.
I lowered my C5 estate for a while - front and rear - the old skool way (adjusting the clamps on the ARB's).
It was fine, no damage done and no bottoming out (either on the suspension travel or the bottom of the car). Likewise it didn't confuse any other systems on the car that may be linked to knowing what the suspension height should be. The only drawbacks were;
- The ride did suffer a bit (it became slightly more 'bouncy' over quickly undulating roads - and this may even have been fine if the spheres were new rather than 15 years old).
- The lowered height doesn't suit unloaded twin-axle trailers (the tow hitch is lower, which pitches the twin axle trailer nose down and consequently makes it bounce a lot, making the rear of the car over-react as a direct result)
The ride wasn't a real problem, the main reason I put the car back to standard was the effect when towing an unloaded trailer (loaded was fine, incidentaly).
it all depends how much you want to lower it by.