I've got a 2001 Infiniti I30 Touring package (which includes the
"sports" tuned suspension).  The car has always had something of a
"bumpy" ride when going over bad portions of roads (potholes, speed
bumps), but overall I've felt the ride was smooth when the road was
fine and have been pretty happy with the ride.

However, I recently bought a new house that is located down a few
streets which are kind of beat up.  Not that the concrete is very
chewed up, it just seems like the land underneath the road has been
somewhat seismically active or something, so there are lots of bumps
and dips, but especially what feels like "seams" in the road (even
though I can't see anything).  Basically, the car is bopping up and
down significantly over this stretch, and despite it only being a few
streets long, I seem to have managed to get car sick each time I've
driven it (not good considering I'm going to be living there).  I
suspect this is at least partially due to the stiff suspension in the
car, which always seemed to transfer those types of acute bangs into
the car.

Any suggestions on how I can improve this?  I know very little about
cars.  Would changing out the shocks help?  If possible, I'd like to
find a way to improve this without doing something that couldn't be
easily reversed if it turns out I don't like it.  I'm a little
concerned about overcompensating and making the ride too smooth (i.e.,
mushy), which is not something I like either.  I'm just wondering if
the age of the car may have something to do with it.