Ritchie,
Thanks for posting the page out of the workshop manual that describes the ride height measurements. And specifically, for anyone interested in checking and/or changing their ride hieght, take note of the procedure, as it isn't exactly intuitive. For the front, measure from the head of the bolt securing the caster block to the chassis to the ground (if you have the D1R lower brace, add the thickness of the bracket to your measurement), and the height from the center of the wheel to the ground, and subtract the former from the latter. At the rear, it's the difference between the distance from the center of the wheel to the ground, and the distance from the center of the torsion bar carrier (that tube-shaped that protrudes out laterally a few inches in front of the rear tire) to the ground. So it isn't quite as simple as slapping a tape measure against the fender wells and measuring to the ground.
As long as the OP doesn't plan to track his car, and only wants to lower it a little bit, he should be fine. But if he ever wants to track the car, and wants to lower it significantly, he needs to get a PhD in mechanical engineering first, as things get incredibly complicated in a hurry. Lowering the center of gravity is a good thing, but lowering these cars has other consequences that open a huge can of worms. It can all be compensated for, but not without delving deep into the dark world of instant centers, roll centers, roll couple lengths, suspension frequencies, the impact all this has on front-to-rear roll stiffness, etc.
