H&R had a 3.5SE Altima that they had just finished installing prototypes in when I was there this afternoon. Looked fine.
The problem you talk about with the suspension settling after several days is because you failed to loosen all suspension pivot points and then retighten them with the full weight of the car on the ground per instructions in all factory/aftermarket manuals.
Failure to follow this instuction will cause premature bushing failure due to a continual torsional preload on the bushings.
Today was only a verification of factory installed suspension pieces and settings on the 350Z, nothing too exciting. They aren't sure if they will be producing anti-sway bars for the 350Z yet, they have just started doing anti-sway bars for the German cars and also have to evaluate the potential customer volume level for the 350Z.
Camber changes on the front end are a concern of theirs, they may end up doing less of drop on the front due to the fact that the rear is approx 12-13mm higher on the car stock than the rear. This may be why the TEIN drop is .8" front and 1.3"rear.

 

VQracer did you ever look into skunk2? do they make coil overs for the Z? I bought a couple sets of those for past cars and I never had problems with them.

 

johnlotusboy the springs settling has nothing do to with a poor installation or improper tightening.

The physical SPRING will relax while the weight of the vehicle is sitting on it. IT takes some time before it reaches a fully relaxed state. Im not a moron, your going to have to trust me on this one.