This begs the questions. Why do rev heads feel the need to lower their cars? What on Earth are they possibly trying to achieve by doing this? Roads are not straight, and then there's speed humps. You have to slow down to like 5km/h (or slower) and if possible, use the edge of the hump rather than the middle.
Lower centre of gravity = better handling (and in my opinion easier to get into), and less chance of lifting at higher speeds.
The higher the car the greater chance to roll it (and many, many SUVs have rolled over from the softest of crashes - even current models). The higher the car the more unstable it is, which means things like the YAW and Moose test, often result in the car on it's side.
That said take the example of rally cars. They aren't slammed on their arse (and going too low is a thing), but their suspension is designed to cope with uneven/loose terrain at high speeds. In rally cars case though, it's all about the lead in/lead out of the corner. If you're turning one of them AT the corner, you're about to crash. Thus my admiration for WRC drivers and co drivers, because often they are being called (and responding to) corners that might be 2-3 and even 5 ahead.
Co Drivers for example will call a series of notes:
Left/Right - Direction of corner
9-1/6-1/1-6 - Speed / tightness of corner - 1 is normally slower first gear hairpin, and 6 is a friggin fast sweeper. Some drivers use a slightly different system (Jemba IIRC).
50-200 - Distance to corner.
And - less than 50m to next corner.
Into - sweeping/connecting corner.
Crest - slight raise in road.
Jump - wheels off the ground.
OC - Off Camber
Care - Caution
Caution - extra care
Double Caution - REALLY careful
Triple Caution / Danger - Stuff it up and you're dead or having a big prang.
So you might hear (as a driver): 1 right 50 into 5 left caution OC 200 Straight and 1 left over crest into 1 right 60 danger.
Which would mean: Tight (slow) right in 50m connecting onto Sweeping fast left off camber (so be careful), immediately onto 200m straight then immediately tight left over a slight raise in road immediately into a slow right hander in 60m which is dangerous.