I have some unfortunate news for you as the Pro-163 is an analog voice only scanner and VIPER operates in a mostly digital voice format which means your monitoring capability of the system will be extremely limited.
Yes do not do that that scanner would work for several users here in the forums you could get a fair price if it is in good shape between $50 to $100 if you list it in the classifieds. That would go toward a scanner that would fit your needs.