You would need a fuel enrichment module, WOT position switch, nitrous nozzles (2), bottle holder brackets (don't see any), re-calibrate the RPM switch to work on a Viper and some short nitrous lines for the plumbing to the throttle bodies. If your going to use a wet kit you will also need a fuel solenoid (don't see one in the pics). You will need to make a complete new wiring harness from scratch. You also want to check the type of fuel safety switch and fuel pressure gauge if you plan on using them. Are they high pressure type ~50psi or low pressure ~10psi? All of the solenoids should be rebuilt prior to use including the bottle opener (it's not hard to do) The kit looks to have two nitrous solenoids, which should be OK to use one for each of the two throttle bodies. However they will need to be reconfigured to be in parallel to the nitrous line, right now they are in series. The nitrous solenoids are small so one by itself will not be enough to flow a big shot, limit maybe 125HP per solenoid. To get a NOS kit for a Viper with all of the add on's that's included in this auction would run you around $1,500 or so.
A good idea would be to wait a couple of months when these DIY supercharger kits come out. There will be quite a few people trading in nitrous kits for a supercharger so look in the classifieds.