The suspension of a Jazz isn't great because it does not have much travel. If it's on 15-inch wheels with 60 of 65 profile tyres it's worth dropping the tyre pressures a bit (not lower than 28PSI all round; I use 30PSI all round on everything). I dropped the pressures of a new HR-V to 30 all round and it transformed the car's ride. Still no good, look at something French like a Citroen C3, but make sure it comes on 15-inch wheels with 65 profile tyres. An oddball small car that rides exceptionally well for its size it a Chevrolet Spark.