I probably don't have any right to comment here, since I've never come any closer to the Challenge than the pages of the magazine.
But since I've been reading the magazine for so long, let me just (politely, I hope) add my .02 about the "big picture", beyond who actually wins the Challenge.
My impression of the first Challenge ($1500, remember?) was that GRM wanted to show folks `sitting on the fence' about participating in our sport that you don't need to be the offspring of an Unser or an Onassis to participate. That desire and cleverness still goes a long way in a sport that seems to be nothing but an endless search for money.
IMO, there is nothing that expresses the desire more than rolling up your sleeves, dragging out the wrenches and the welder, and doing the work yourself. There is nothing that expresses the cleverness more than rummaging through a hundred rusty wrecks, searching for parts that fit into the blueprint inside your head.
Again, IMO, a claiming rule without taking the labor into account would insult the people with the desire and cleverness. I can see that some of the extravagant Challenge cars (the Zamboni/the Nelson's Bug, etc.) might send some of those `fence-sitters' back towards giving up on the sport..but look at Hong Norr's CRX! It's really not much different than the kind of thing any other "sport import" curious college kid could build. And looking at the rest of the field, most of the cars seem to be much in the same vein.
It's a question as old as amateur motorsport itself. Is it about winning the thing at all cost, or is it about just getting out there, having a good time, and doing the best you can with what you have? I've never won a motor race (I once ran SCCA ITB). I've never won an autocross (I now run SCCA ST). But I've sure beaten some of the "offspring of Onassis" I mentioned before. And when you've done the best you can with what you have, it's still a very rewarding sport.
Sure, I'd like to win something someday...but if the choice is between racing without winning, and not racing at all, I pick racing without winning, just to be doing it. My life is so much richer actually doing this, instead of simply dreaming about it that I don't care about my mediocrity. Even being a mediocre racer makes me much more than a mediocre person, simply because I'm a racer, instead of a watcher. I'm all for searching for the "Unfair Advantage" (as Donahue called it) within the rules, but seeking to change the rules simply because you're losing might be a sign that you need an ego check.
Apologies for the rant, I'll shut up now...