My son and I ran (and both made it) in the 150 Club last year in his nearly stock, daily driver 350Z that we drove to the Salt. We ran the stock, closed end lug nuts. I don't remember the inspectors showing much interest in them in tech, but I suppose you could always pull one to show 'em you've got adequate thread. They're not mentioned in the 150 Club rules on their web site, either.
We just did the stuff listed on the rules as per the website, and didn't really have much problem. One inspector was talking about leg restraints (full door opening net), but we had a copy of the rules with us, it wasn't listed as a requirement, and we prevailed. The inspectors rightly have the final say on these things, and should err on the side of safety, but if it isn't listed in the rules...
Anyway, you can always call the number on their website, and Ellen will hook you up with an inspector.
Jeff in Boise