You probably should test it at least once at the speed of 110-120 km/h for about 5 minutes. Some problem it's eaiser to be caught at higher speed. For example, if the car had some un-balance problem on the axile or suspension, it's hard to notice at 40 km/h, but you can feel the vibration easily at 120 km/h.
Also, Honda's engine is quite loud at higher speed, (design issues, usually not machinical defect), you may want to have a idea about the noise level before you buy it.
