I don't have any addititional info yet on the Akrapovic exhaust other than the price. I've intially ordered 3 out of 9 coming to North America and all with Carbon tailpipes. Yes they will fit the Nismo and the power will most likely be in line with other high end systems on the market. The main difference will be unrivaled quality, exclusivity and real carbon tailpipes. I'll be doing some documentation and video once I get one for my car.
Thanks.
Pat