I've called Nippon themselves, but either they don't speak english or don't know what i'm talking about....

I am going to get the black chrome McGard splinedrive wheel lock/lug kit, part #MCG-65457BK. I know they are the right size for my studs, but i want to know if they will fit on my wheels securely. I have Nippon Racing F2 wheels. 15X6.5", 40offset. Do my nippon wheels have a tapered seat that the McGard wheels will fit securely too or do the wheels have a radius or flat seat that the McGard lugs won't grip well too??? Since the McGards are the tapered/tuner style, I want to know if my nippon wheels are also the tapered/tuner style and the McGards will match up flush and securely.

hope my question isn't too confusing. thanks for any input.

-Rob