Look how far the RPM's drop from 2nd to 3rd and from 4th to 5th. No wonder Z06's had such an advantage over the Vipers stock to stock. Dropping down to 4,500 rpm's after a shift is horrible gear spacing.
I believe you mean "ZR1s" as the C6 Z06 has tall 5th and 6th gears as well. The ZR1 has a close ratio tranny.
This issue is easily addressed with a <$2k 5th and 6th gear swap (or purchase of a 2010 Gen IV Viper that has the closer 5th gear).
Practically speaking, you will rarely see the problem with the tall 5th and 6th gears since you can hit 150-160 mph in 4th and you will not exceed about 165 mph on most road courses for a HPDE. If, on the other hand, the Standing Mile/closed circuit events are a regular occurrence, then just swap the gears! If you are consistently going faster than 155 mph, then you should also have additional safety equipment, etc.