The difference between the Viper in Caprica and the Viper in BSG:TOS is like the difference between a WWII P-38 Lightning and F-35 Lightning II. Same name, different generation of aircraft. The difference between the Mark I Viper from TOS and the Mark IX(?) Viper in the re-imagined series is like the difference between an F-15A and an F-15E. Same plane, but upgraded.
Spot on there chap, very good way of explaining it..