The KAMIKAZE Varis kit is every wider than than vented fenders, which are 10mm. I couldn't find exact measurements but its probably around 1.5 - 2 INCHES wider than stock - thats ALOT of body work to make the fenders/sideskirts flow with a stock bumper.
At that rate you're dropping the car off to a body shop and doing some major fab work, because you're going to need to cut and rivet/mold on REAR over fenders as well to match up the width. And the Varis KAMIKAZE stuff is already thousands of dollars. There are maybe 3 in existence (Varis, Galeforce, and one drift team IIRC)
The regular Varis vented fenders are also going to need some work to flow with a nismo bumper because those add on pieces don't quite line up, at least for the 15+ Nismos
Here is instagram user altargtz25 (private):
Even with this small image you can see the gap in the front/lower tip of those fender extensions