Whenever I drive over speed bumps (or pot holes or whathaveyou) I notice that when the rear wheels go over, the whole car jumps up and down and clatters, a lot more so than the front wheels. I am pretty sure the shocks are not the issue here, partly because I've changed them and the behavior didn't go away and partly because the problem is not that the back is too bouncy, it's that it's too stiff. It almost seems like there's something wrong with the coil springs, but they look fine and I have no idea how to test them otherwise... Any ideas?
The car is an Acura Integra from '93, a sporty hatchback.