Yea I was left wondering the same thing since I was curious what the deal was. Turns out its a drift car, and the skyline started life off as a base model GTS so yea the V8 was a improvement. I googled a little and came up with this.
Another video of the car in action!
http://videos.streetfire.net/recentvideos/2/078c22e6-7599-4910-a665-9907008252e0.htm
Site of the buildup here.