I am not expert in Nos but I spent my saturday morning to look for a new set of plugs for a supercharged car. Search for "NGK plug" under the forums. You will find plenty of use full information for NOS. NOS requires special care regarding plugs. My friend uses NGK BKR8EIX to run 150 NOS. Here are the plugs that you should NOT USE:
Bosch FR8DC #7527 : Comes with Roe SC, a little to hot for my set up.
NGK FR4 : Same heat as Bosch FR8DC
NGK FR5 : I will use this one with the Supercharger
NGK FR5-1: Same as stock stock Champion plug with extended electrode
With NOS you should go in much colder plugs and should avoid using Platinium plugs due to chimical reaction. Personnaly I prefer the NGK FR serie because the cup on the top of the plug is fix.
Have a look on the web site
www.roeracing.com they have great supercharger kits (600-700hp) for Vipers like yours. Sean Roe, the owner, provides an outstanding customer service. NOS is cheaper but ******* the mechanic.