One way to see the cells is to get the car on a lift & trace the hydraulic lines - the spheres themselves are inside the car, though, so all you'll do is locate their hydro connection points. Inside the car, you'll need to remove the panel between the folding, rearmost seat back, and the back seat (middle row). With that panel removed, the spheres are right there (I replaced mine about a month ago). Essentially, the cells are inline with the shocks, but more inboard/towards the center of the car.
If your car is bouncy or abrupt in dealing with bumps, it's cell time. Mine rides like a new car now, and I'm still on my original shocks (184k miles)!
"If everything seems under control, you're simply not going fast enough" --Mario Andretti
1995 E500 street car
1986 Porsche 944 Turbo S track car