Mergnthwirker

The 370Z changed the front suspension to be more of a double wishbone suspension rather than a straight McPherson strut type. But it's really not all that different. The rear suspension is pretty much the same (I think -- I've never owned a 350Z-- someone please correct me if I'm wrong?).

If you define coilover as concentric shock/spring units, then the Z has a coilovers in the front, but separate mounting locations for the spring and the shock in the rear.

Aftermarket "coilover's" duplicate the stock layout for this car (not true for many other vehicles), but provide three big advantages:

1. different -- usually stiffer -- spring rates and shock valving than stock. Those with progressive springs can give you a softer initial rate that stiffen up as they are compressed. The shock valving of the "coilover" is supposedly matched to the spring rate to provide just the right amount of damping to keep the wheels planted as much as possible, and prevent oscillation of the suspension. The net effect is (maybe) a better ride, but certainly a car that is better glued to the road!

2. They also provide the ability to change the ride height by moving the spring perch up or down. For non-race use, this might be their primary benefit -- a lowered meaner "look"

3. They may provide shock valving adjustment. The best ones give you the ability to adjust the shocks control of the springs in both the compression stroke (when you hit a bump) and in the rebound stroke (when the spring pushes the suspension back). This level of shock control is particularly useful on race courses. Maybe less so on autocross, where an overall stiff, flat chassis is desirable.

As others have suggested, there's lots of information about suspension design on the web. Don't get hung up on the term "coilover." Think instead of "shocks/springs that allow me to tune my suspension" every time you hear the word coilover.

Hope this helps!