Breaking a Cardinal Rule?

I have forgotten to mention that this is the last week until I begin tapering for the White Rock Lake Marathon in Dallas. One more week with a Saturday 22-miler hanging over my head. One more Friday where I'm in bed wayyyyyyy too early so that I'm fresh for the next day's long run. This will be my third marathon and the saying still holds true: The marathon training is much tougher than the marathon itself.

Even though I can see the finish line, there is still a little work to be done. Since Oct. 25, every run I'd done in my Brooks Adrenalines was causing some pain in my left big toe.
At first it felt like I had a rock in my shoe. Then it felt like I stubbed my toe on something. It felt arthritic.
And something else about my Adrenalines: They had this strange wear pattern on the outside of the shoes, like I had toooo much support. So Monday, I broke the cardinal rule of never trying a new kind of shoe this late in the marathon training by buying a new kind of shoe this late in the marathon training.
I stayed with Brooks, but got the Brooks Infiniti. Still gives me some support, but they dont push my feet out as much as the Adrenalines did.
Everytime I buy a shoe that isnt an Adrenaline, I have some kind of problem, like blisters with the Addidas Supernovas or shin splints with the Asics 2130s. Ive run in the Infinitis twice already and my feet feel good. There is some rubbing that may give me a blister under my right foot, but I think thats because of the way the insole rides high inside the shoe. (OK, that's the excuse I'm making up. They feel sooo good except for that nagging little thing) Nothing a pair of scissors cant fix. These Infinitis are light, much lighter than the Adrenalines, but I don't think I'm giving up anything in terms of the support I need.
Still, I won't know for sure until I've put them on the road for a two-hour plus run. If all hell breaks lose, believe me, I'm going back to the Adrenalines. It'd be a shame to wreck my marathon performance because of some new shoes. I know I can get through 3 1/2 hours with an achy big toe in the Adrenalines. I don't want to take the chance of the unknown in the Infinitis