Nissan bought out a R34 GTR V-Spec II Nur (Nur) short for Nurburgring, the famous race track in Germany.
I read that it was to comemorate the GTR being the fastest production car at that time... I think only in Japan... I gota read the mag I bought again, awhile back.
The Nismo one you posted is a R34 GTR which was tuned by Nismo / Omori Factory, A V-Spec II (Could be a V-Spec II model, not sure cuz there is no badge in the pics) model with all Nismo upgrades on the car.
I think this is the right order...
GTR - Standard GTR
GTR V-Spec - Suspension upgrades / updated ATTESA E-TS
GTR V-Spec II - Suspension upgrades / updated ATTESA E-TS / afew things revised
GTR V-Spec II N1 - As of above with upgraded turbos
GTR V-Spec II Nur - As of above
GTR V-Spec II M1 Nur - As of above with upgraded turbos / leather seats (heated, I think) with gold trimings / softer suspension / champagne gold body colour
GTR V-Spec II S1 (S-Tune) - Upgraded with Nismo parts / internal upgrades
GTR V-Spec II S2 (S-Tune) - Upgraded with Nismo parts / internal upgrades / tune for higher power
GTR V-Spec II R1 (R-Tune) - Upgraded with Nismo parts / internal upgrades / tune for higher power / Race Spec engine
GTR V-Spec II Nismo Z-Tune - Upgraded with Nismo parts / internal upgrades / tune for higher power / Race Spec engine / ULTIMATE Street car
GTR JGTC (Japanese Grand Touring Car)
I think thats how it goes with all the explanations... Someone correct me if I have missed something / anything...