Skip them. When I first bought my jeep and got new wheels and tires for it, I opted for new lug nuts. I chose a wheel lock kit, not spline drive, but the concept is the same. I've lost 3 sockets in 3 years. It costs me 20 bucks every time and leaves me unable to take my wheel unless I'm willing to pound one of my existing good large sockets on and ruin it for that one time job.
What happens is I put the wheel lock key on the lug nut and forget to take it off, then I drive away and it falls off. After 3 times of doing that, I've had enough.
Just use standard lug nuts. If a thief wants your wheels, he's gonna figure out a way to get them.
And as Chris said, you'll be a lot more likely to find someone with a standard socket than your rare splined socket, if you were to ever need it someday.
